Number + 言
The noun 言 (yán) literally means "word" or "speech," but in the context of classical Chinese poetry, it functions as a unit of meter referring to the number of characters per line. For example, 七言 means "seven-character verse," indicating each line has seven characters.
唐代最有名的诗歌形式是五言和七言。
Táng dài zuì yǒumíng de shīgē xíngshì shì wǔyán hé qīyán.
The most famous poetic forms of the Tang Dynasty were five-character and seven-character verse.
这首五言诗读起来特别有节奏感。
Zhè shǒu wǔyán shī dú qǐlái tèbié yǒu jiézòugǎn.
This five-character poem has a particularly strong sense of rhythm when read aloud.
老师让我们背一首七言律诗。
Lǎoshī ràng wǒmen bèi yì shǒu qīyán lǜshī.
The teacher asked us to memorize a seven-character regulated verse.