A local homeomorphism is a map 𝑓:𝑋→𝑌 between topological spaces
such that every 𝑥∈𝑋 has a neighbourhood 𝑈 such that 𝑓(𝑈) is open and 𝑓↾𝑈:𝑈→𝑓(𝑈) is a homeomorphism. #m/def/topology
Equivalently, 𝑓 is a local homeomorphism iff 𝑓 is continuous, open, and locally injective.