溝 - gutter, ditch, sewer

oceanic trench; deep-sea trench; deep

ditch; drain; gutter; trench

ditch; drain; gutter; trench

bird cherry (Prunus padus)

lateral sulcus (brain structure); Sylvian fissure; lateral fissure

sulcus; groove in the surface of the brain

Chinese pond mussel (Sinanodonta woodiana)

subterranean drain; culvert; conduit

mammary slit (in whales, dolphins and porpoises)

ditch; sewer; canal

Marco Polo Bridge (China)

grooved rail