(law) an explanation of the fundamental reasons (especially an explanation of the working of some device in terms of laws of nature); "the rationale for capital punishment"; "the principles of internal-combustion engines"
(usually plural) small personal articles or clothing or sewing items; "buttons and needles are notions"
a general inclusive concept
an odd or fanciful or capricious idea; "the theatrical notion of disguise is associated with disaster in his stories"; "he had a whimsy about flying to the moon"; "whimsy can be humorous to someone with time to enjoy it"
an unexpected and inexplicable change in something (in a situation or a person's behavior, etc.); "the vagaries of the weather"; "his wealth fluctuates with the vagaries of the stock market"; "he has dealt with human vagaries for many years"