What is the meaning of -요?

A particle attached to intimate-style verbs and adjective endings and some blunt-style endings to form the polite style, the usual speech level for polite but not extremely formal conversation, e.g. by a student to a teacher, a child to a parent, or between colleagues.

A particle attached to substantives, adverbs, or non-sentence-final endings to show respect to the listener in the polite style.

Gyeongsang and Jeolla dialect form of (-o, post-vowel allomorph of (-so, semi-formal style sentence-final suffix)).

Source: wiktionary.org