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