Merriam-Webster's Collegiate® Dictionary, 11th Edition
MUSE
I. verb (mused; musing)
Etymology: Middle English, from Anglo-French muser to gape, idle, muse, from Old French *mus mouth of an animal, from Medieval Latin musus
Date: 14th century
intransitive verb to become absorbed in thought, wonder , marvel , transitive verb to think or say reflectively, see: ponder muser noun
II. noun
Date: 15th century
a state of deep thought or dreamy abstraction,
III. noun
Etymology: Middle English, from Middle French, from Latin Musa, from Greek Mousa
Date: 14th century
any of the nine sister goddesses in Greek mythology presiding over song and poetry and the arts and sciences, a source of inspiration, poet