Definition of "Cheer" :

noun: the quality of being cheerful and dispelling gloom

"Flowers added a note of cheerfulness to the drab room."

noun: a cry or shout of approval

verb: show approval or good wishes by shouting

"Everybody cheered the birthday boy."

verb: spur on or encourage especially by cheers and shouts

"The crowd cheered the demonstrating strikers."

verb: become cheerful

verb: cause (somebody) to feel happier or more cheerful

"She tried to cheer up the disappointed child when he failed to win the spelling bee."

verb: give encouragement to