trend / trend/ • n. a general direction in which something is developing or changing: an upward trend in sales and profit margins. ∎  a fashion: the latest trends in modern dance.• v. [intr.] (esp. of geographical features) bend or turn away in a specified direction: the Richelieu River trending southward to Lake Champlain. ∎  change or develop in a general direction: unemployment has been trending upward.

trend †revolve, roll OE.; take a specified direction XVI. OE. trendan, f. Gmc. *trend- *trand- *trund-, repr. also by OE. trinda round lump. ball, ātrendlian roll away; cf. TRUNDLE.
Hence trend sb. the way something turns away, general direction. XVIII.

trend The azimuth of a geologic feature, commonly of a fold axis, and written as a compass bearing.