Сегодняшний урок короче вчерашнего.

Today’s lesson is shorter than yesterday’s.

Breakdown of Сегодняшний урок короче вчерашнего.

• урок: the lesson
• вчерашний: yesterday's
• сегодняшний: today's
• короче: shorter

Questions & Answers about Сегодняшний урок короче вчерашнего.

Why doesn’t the sentence use a word for is, like есть?

In the present tense, Russian normally leaves out the verb to be (быть) in sentences like this.

So instead of saying Сегодняшний урок есть короче вчерашнего, Russian just says Сегодняшний урок короче вчерашнего. The is is understood from the structure: [subject] + [adjective].

What exactly does сегодняшний mean, and how is it different from сегодня?

Сегодня means today (an adverb).

Сегодняшний is an adjective derived from сегодня and means today’s / of today.

• Сегодня урок. – The lesson is today.
• Сегодняшний урок. – Today’s lesson.

In your sentence, Сегодняшний урок literally means today’s lesson.

What form is короче, and what is the basic adjective?

Короче is the comparative form of the adjective короткий (short).

• короткий урок – a short lesson
• урок короче – the lesson is shorter

So короче = shorter. It’s the standard, single-word comparative form, very common and natural.