We introduce and investigate ω_s-open sets as a new class of sets which are strictly between open sets and semi-open sets. Then we use ω_s-open sets to introduce ω_s-continuous functions as a new class of functions between continuous functions and semi-continuous functions. We give several results and examples regarding our new concepts. In particular, we obtain some characterizations of ω_s-continuous functions.
Semi-open set, ω-open set, Semi-continuous function