Yes, STRAND is a Scrabble word!

Letter values in Scrabble US: S 1, T 1, R 1, A 1, N 1, D 2.

Is it a valid word?

STRAND is a valid word in the official Scrabble dictionary (US), the UK Scrabble Dictionary and Words with Friends (ENABLE).

a pattern forming a unity within a larger structural whole
line consisting of a complex of fibers or filaments that are twisted together to form a thread or a rope or a cable
a necklace made by a stringing objects together;
a very slender natural or synthetic fiber
a poetic term for a shore (as the area periodically covered and uncovered by the tides)
a street in west central London famous for its theaters and hotels

Also: run aground.