The Collaborative International Dictionary of English v.0.48:
Sunbeam \Sun"beam`\, n. [AS. sunnebeam.] A beam or ray of the sun. "Evening sunbeams." --Keble. [1913 Webster] Thither came Uriel, gliding through the even On a sunbeam. --Milton. [1913 Webster]WordNet (r) 3.0 (2006):
sunbeam n 1: a ray of sunlight [syn: sunbeam, sunray]