45 noun1 •A gramophone record played at 45 revolutions per minute.Once he almost fell asleep, and then the little record player started up in his mother and father's bedroom. Mom was playing her scratchy Elvis 45s again. — 1991 forms45's · 45s
.45 noun1 •A standard kind of firearm designed to fire bullets that are approximately 0.45 inch in diameter.He was wearing the normal jungle fatigues and had a .45 in a holster on his waist. — 2013 forms.45s
