1ace 
/ˈeɪs/ noun
plural ac·es /ˈeɪs/ noun [count] 1 : a playing card with one large figure in its center that can be the card with either the highest or lowest value
▪ the ace of spades/diamonds/hearts/clubs — see picture at playing card 2 : a person who is very skilled at something
▪ a computer ace ▪ the ace of the team's pitching staff [=the best pitcher on the team] — often used before another noun ▪ an ace mechanic/reporter 3 : a point scored on a serve that an opponent fails to hit in tennis
▪ She won the match by scoring more than 30 aces. 4 US : a score of one on a hole in golf : hole in one
▪ He got/shot/scored an ace on the eighth hole.
▪ the ace of spades/diamonds/hearts/clubs — see picture at playing card
▪ a computer ace ▪ the ace of the team's pitching staff [=the best pitcher on the team] — often used before another noun ▪ an ace mechanic/reporter
▪ She won the match by scoring more than 30 aces.
▪ He got/shot/scored an ace on the eighth hole.
an ace in the hole (US) or chiefly Brit an ace up your sleeve
◊If you have an ace in the hole or an ace up your sleeve, you have a powerful and often secret weapon, advantage, etc., that you can use if it is needed.
▪ The mayor's popularity among elderly voters gives him an ace in the hole for the coming election.
▪ The mayor's popularity among elderly voters gives him an ace in the hole for the coming election.
hold all the aces
: to have a strong advantage over others in a contest, competition, etc.
▪ As the strike continues into its second week, it appears that the company holds all the aces in its negotiations with the strikers.
▪ As the strike continues into its second week, it appears that the company holds all the aces in its negotiations with the strikers.
within an ace of
informal : very near to (doing something)
▪ They were/came within an ace of winning the championship. [=they almost won the championship]
▪ They were/came within an ace of winning the championship. [=they almost won the championship]
