regular tetrahedron

a waterway, more specifically, a navigable channel / a wake (path left behind by a passing ship on the water's surface)

temperate rainforest

an orangutan

One should be able to derive new understanding while revising what he has learned. Learning from the past.

air temperature, atmospheric temperature, ambient temperature

a male given name

(music) music box

Georg

a chariot: a horse-drawn vehicle with two wheels and usually one or two riders