Adverb
noun, の adjective
This is like your side part of speech, as in, you add it to the side of a verb because it's an adverb.
ふくし
This is a jukugo word, which usually means on'yomi readings from the kanji. If you know the readings of your kanji you'll know how to read this as well.
私は昨日、日本語の時を表す副詞を学びました。
I learned Japanese adverbs that show time yesterday.