Yes, FOOTHOLD is a Scrabble word!

Letter values in Scrabble US: F 4, O 1, O 1, T 1, H 4, O 1, L 1, D 2.

Is it a valid word?

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

an area in hostile territory that has been captured and is held awaiting further troops and supplies
a place providing support for the foot in standing or climbing
an initial accomplishment that opens the way for further developments