Yes, MORPHOLOGY is a Scrabble word!

Letter values in Scrabble US: M 3, O 1, R 1, P 3, H 4, O 1, L 1, O 1, G 2, Y 4.

Is it a valid word?

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

the branch of biology that deals with the structure of animals and plants
studies of the rules for forming admissible words
the admissible arrangement of sounds in words
the branch of geology that studies the characteristics and configuration and evolution of rocks and land forms

Also: sound structure, syllable structure, word structure.