Learn Hardcore Russian: Фонарь освещает тротуар вечером. - The streetlight lights the sidewalk in the evening.

Typical word order
Russian often uses Subject–Verb–Object order, especially in neutral sentences.
So the first noun (фонарь) is very likely the subject, and the noun after the verb (тротуар) is likely the object.
Case
- Фонарь is in the nominative case (dictionary form), which is used for the subject.
- Тротуар is in the accusative case as the direct object.
However, for masculine inanimate nouns like тротуар, the accusative form is identical to the nominative (both look like тротуар). You know its role here mainly from word order and meaning.

So: фонарь (nom.) is doing the action, тротуар (acc.) is receiving it.

What gender is фонарь, and how can I tell?

Фонарь is masculine.

Clues:

Meaning
It’s an inanimate object (a lamp/streetlight), but that alone doesn’t tell you the gender.
Ending in the nominative singular
- It ends in a soft sign ь. Nouns ending in -ь can be masculine or feminine; you have to learn them individually.
- Many masculine nouns with -ь end with a consonant + ь (e.g. словарь, компьютер doesn’t have ь, etc.), but this is only a tendency, not a strict rule.
Dictionary form
Dictionaries mark gender: фонарь, м. (м. = masculine).

So for -ь nouns you usually have to memorize the gender, and фонарь happens to be masculine.

Why does тротуар look like the dictionary form if it’s the object? Shouldn’t it change?

Тротуар is the direct object, so it is in the accusative case.
But for masculine inanimate nouns, the accusative singular = nominative singular.

Nominative singular: тротуар – “(the/a) sidewalk” (subject form)
Accusative singular: тротуар – “(the/a) sidewalk” (object form)

They look the same, but function differently.

Compare with a masculine animate noun (e.g. “man”):

Nominative: человек – “a man” (subject)
Accusative: человека – “(I see) a man” (object; form changes!)

So no visible ending change here doesn’t mean it’s nominative; you know it’s object because:

it comes after the verb and
the verb освещать normally takes a direct object.

What exactly is вечером grammatically, and why does it use this form to mean “in the evening”?

Вечером is the instrumental singular of вечер (“evening”), but it functions as an adverbial time expression: “in the evening”.

In Russian, one common pattern to answer “когда?” (when?) is:

Instrumental singular without a preposition:
- утром – in the morning (from утро)
- днём – in the daytime (from день)
- вечером – in the evening (from вечер)
- ночью – at night (this one is a fossilized form)

So вечером literally is a case form of вечер, but idiomatically it means “(at) evening time / in the evening”.

Alternatives (with slightly different nuances):

по вечерам – in the evenings / in the evenings regularly
каждым вечером – every evening
в этот вечер – this evening (a specific one)

Here, вечером is the most natural choice for a general, habitual time (“in the evening” in general).

What tense, aspect, and person is освещает, and what is the infinitive form?

Освещает comes from the infinitive освещать.

Grammatically, освещает is:

Tense: Present
Person: 3rd person
Number: Singular
Aspect: Imperfective (ongoing, repeated or general action)

So освещает means roughly “(he/she/it) illuminates / is illuminating / lights (up)” in a general or habitual sense.

Full present-tense conjugation of освещать:

я освещаю – I illuminate
ты освещаешь – you illuminate (sing. informal)
он / она / оно освещает – he / she / it illuminates
мы освещаем – we illuminate
вы освещаете – you illuminate (pl. or formal)
они освещают – they illuminate

In our sentence, фонарь = он (he/it), so we use освещает (3rd person singular).

Why do we use imperfective освещает, and how would the meaning change with perfective forms like осветит or осветил?

Освещает (from освещать) is imperfective. It describes:

a general fact: what the lamp does in the evenings
an ongoing or repeated action

So Фонарь освещает тротуар вечером = the lamp (generally) lights the sidewalk in the evening (habit / regular situation).

If we use the perfective verb осветить, the meaning focuses on a single, completed event:

Фонарь осветит тротуар вечером.
– “The lamp will light up the sidewalk in the evening.”
(one-time or result-focused future action)
Фонарь осветил тротуар вечером.
– “The lamp lit up the sidewalk in the evening.”
(completed action in the past, result realized)

So:

освещает – describes a process or usual behavior
осветит / осветил – describe a completed act with a result

Can I say Фонарь вечером освещает тротуар or Вечером фонарь освещает тротуар? Does the word order matter?

Yes, both are correct:

Фонарь вечером освещает тротуар.
Вечером фонарь освещает тротуар.

Russian word order is flexible, and changing it mostly affects emphasis, not basic grammar.

Nuances:

Фонарь освещает тротуар вечером.
Neutral; focuses on what the lamp does and just adds “in the evening” at the end.
Фонарь вечером освещает тротуар.
Slight emphasis on “evening” as the time when this happens (as opposed to some other time).
Вечером фонарь освещает тротуар.
Stronger focus on “In the evening …” as the starting point of the information; you set the scene first (“In the evening, the lamp lights the sidewalk.”).

Grammatically, the roles (subject, verb, object) don’t change; only informational emphasis does.

What’s the difference between освещать тротуар and something like светить на тротуар?

Both involve light, but:

Освещать тротуар
- Verb: освещать – “to illuminate, to light up (something)”
- Takes a direct object in the accusative: освещать + что? → тротуар
- Focuses on the result: the sidewalk is lit/illuminated.
Светить на тротуар
- Verb: светить – “to shine, to give off light”
- Often used with a preposition: светить на + accusative – “shine onto/onto”
- Focuses on the direction of the light: the lamp shines onto the sidewalk.

So:

Фонарь освещает тротуар. – The sidewalk is lit; it’s bright there.
Фонарь светит на тротуар. – The lamp directs its light onto the sidewalk (more about direction than the illuminated state).

Both are natural, but освещает тротуар is a bit more result-oriented.

Why is there no word for “the” or “a” before фонарь or тротуар?

Russian does not have articles like “a/an” or “the”.

Фонарь can mean “a lamp” or “the lamp”, depending on context.
Тротуар can mean “a sidewalk” or “the sidewalk”, also from context.

The sentence Фонарь освещает тротуар вечером could be translated as:

“A lamp lights a sidewalk in the evening.”
“The lamp lights the sidewalk in the evening.”
“A streetlight lights the sidewalk in the evening.”
etc.

Russian relies on context, word order, and sometimes demonstratives (like этот, “this”) to give the same distinctions English makes with articles:

Этот фонарь освещает тротуар вечером. – This lamp lights the sidewalk in the evening.
Один фонарь освещает тротуар вечером. – One lamp lights the sidewalk in the evening. (emphasizing “only one”)

How do I pronounce each word, and where are the stresses?

Approximate pronunciation with stress marked by bold:

ФонА́рь – [fanarʲ]
– Stress on -а́рь. Final -рь is a soft r plus soft sign.
освещА́ет – [əsʲvʲɪʂaɪt]
– Stress on -а́-: о-све-ща́-ет.
– -щ- is like “shch” in “fresh cheese”, often sounds close to a long sh to learners.
тротуАр – [trətʊar]
– Stress on the last syllable -ар.
вЕ́чером – [vʲet͡ɕɪrəm]
– Stress on вЕ́.
– ч is like English “ch” in “church”.

Putting it together (rough guide):
фа-НАРʲ ас-вʲи-ЩА́-ит тра-ту-АР ВЕ́-чирэм (with the stressed syllables capitalized here just for clarity).

Why is the verb in third person singular? Could it ever be plural here?

The verb must agree in number and person with the subject.

Subject: фонарь – one lamp → 3rd person singular (“it”)
Verb: освещает – 3rd person singular present

If the subject were plural, the verb would also be plural:

Фонари освещают тротуар вечером.
– “The lamps light the sidewalk in the evening.”
(фонари – plural; освещают – 3rd person plural)

So освещает is singular because фонарь refers to one lamp.