と

と has three main uses, all unified by the idea of "together with" or "linked to."

Accompaniment: 友達と行く — "go with a friend." Listing nouns exhaustively: 寿司と天ぷらと刺身 — "sushi, tempura, and sashimi" (and nothing else implied — contrast や, which suggests "and other similar things"). Quotation: 「行く」と言った — "said 'I'll go'." The quotation use also covers thoughts (と思う — "think that...") and reported names (とよぶ — "is called X").

This と is the particle と — distinct from the conditional conjunction と ("when / if / whenever"), which attaches to verbs in plain form rather than to nouns. The conditional は documented separately as conditional-to.