Ο βλαστός μεγαλώνει γρήγορα.

Ο is the definite article meaning the.

Here it is:

• masculine
• singular
• nominative

It agrees with βλαστός, which is the subject of the sentence.

It is capitalized only because it is the first word of the sentence. In the middle of a sentence, it would be ο.

The ending -ος is a very common ending for masculine singular nouns in Greek.

In this sentence, βλαστός is:

• masculine
• singular
• nominative
• the subject of the verb

So ο βλαστός means the shoot / the sprout / the stem, depending on context.

μεγαλώνει is the 3rd person singular present form of the verb μεγαλώνω, meaning to grow or to get bigger.

So it matches ο βλαστός:

• ο βλαστός = the shoot
• μεγαλώνει = grows / is growing

It is singular because the subject is singular.

It can mean either one, depending on context.

Greek present tense often covers both:

• The shoot grows quickly
• The shoot is growing quickly

English usually forces you to choose between simple present and present continuous, but Greek often does not.

γρήγορα is an adverb, meaning quickly.

It tells us how the growing happens.

Unlike nouns and articles, adverbs do not change for gender, number, or case here. So γρήγορα stays the same no matter whether the subject is masculine, feminine, singular, plural, and so on.

That is a very natural word order in Greek:

• subject + verb + adverb

So:

• Ο βλαστός μεγαλώνει γρήγορα.

But Greek word order is more flexible than English. You may also see:

• Ο βλαστός γρήγορα μεγαλώνει.
• Γρήγορα μεγαλώνει ο βλαστός.

These alternatives are possible, but they may sound more marked or give a different emphasis. The original sentence is the most neutral and straightforward.

Usually, if you mean the shoot, you keep the article:

• Ο βλαστός μεγαλώνει γρήγορα.

If you remove it:

• Βλαστός μεγαλώνει γρήγορα.

that sounds less neutral and would not normally be the standard way to say A shoot grows quickly either. Greek does not use the indefinite article the same way English uses a/an in every situation, and bare singular count nouns are more limited.

So for a normal sentence meaning the shoot grows quickly, the article is expected.

The accent marks show which syllable is stressed.

So the stress is:

• βλαστός
• μεγαλώνει
• γρήγορα

Stress matters in Greek pronunciation and can also help distinguish words or forms. When learning vocabulary, it is important to learn the accent together with the word.

A rough pronunciation is:

• Ο = o
• βλαστός = vla-STOS
• μεγαλώνει = me-gha-LO-ni
• γρήγορα = GREE-gho-ra

So the whole sentence sounds roughly like:

o vla-STOS me-gha-LO-ni GREE-gho-ra

A few notes:

• β is pronounced like v in modern Greek.
• γ before back vowels is a voiced sound, somewhat like a soft gh.
• The accented syllables are the strongest ones.

Most commonly, βλαστός refers to a shoot, sprout, or young stem of a plant.

Depending on context, English translations may vary:

• shoot
• sprout
• stem

So even if the meaning is already given, it is useful to know that Greek words do not always match one single English word perfectly.

You would change the article, noun, and verb to plural:

• Οι βλαστοί μεγαλώνουν γρήγορα.
• The shoots are growing quickly / grow quickly.

Changes:

• Ο → Οι
• βλαστός → βλαστοί
• μεγαλώνει → μεγαλώνουν

The adverb γρήγορα stays the same.

Yes, depending on context, Greek can sometimes use the definite article in places where English might sound more general.

So Ο βλαστός μεγαλώνει γρήγορα could refer to:

• a specific shoot already known in context, or
• a more generic the shoot in an explanatory or descriptive context

But the most direct reading is still the shoot. Context decides how specific it feels.