Learn Croatian: Tanjur je pun komadića mesa. - The plate is full of small pieces of meat.

The base word is komad (piece). By adding the suffix -ić, it becomes the diminutive komadić (small piece). Nouns ending in -ić are always masculine and decline just like regular masculine nouns.

Why does the diminutive end in -a here (komadića)?

The adjective pun (full) requires the noun that follows it to be in the Genitive case. Because there are multiple small pieces, we use the Genitive plural. For masculine nouns like komadić, the Genitive plural is formed by adding -a, resulting in komadića.

Why is mesa also in the Genitive case?

This is a chain of Genitives! Just like in English where we say "pieces of meat", Croatian uses the Genitive case to show what the pieces consist of. Mesa is the Genitive singular of the neuter noun meso. So the literal structure is "full of pieces (Genitive) of meat (Genitive)."

Why use pun instead of the familiar word puno?

Pun is an adjective here meaning "full", and it must match the masculine subject tanjur (plate) in the Nominative case. You might be used to seeing puno, which is an adverb meaning "a lot" (as in puno mesa - a lot of meat). Here we are describing the state of the plate itself, so we need the adjective.