1 ace /ˈeɪs/ noun
plural aces
1 ace
plural aces
Learner's definition of ACE
: a playing card with one large figure in its center that can be the card with either the highest or lowest value see picture at playing card
: a person who is very skilled at something
often used before another noun
: a point scored on a serve that an opponent fails to hit in tennis
US : a score of one on a hole in golf : hole in one

an ace in the hole

(US) or chiefly British 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.

hold all the aces

: to have a strong advantage over others in a contest, competition, etc.

within an ace of

: very near to (doing something)
2 ace /ˈeɪs/ verb
aces; aced; acing
2 ace
aces; aced; acing
Learner's definition of ACE
[+ object]
US, informal : to earn a very high grade on (an examination) : to get a grade of A on (an examination) : to perform very well on (a test or challenge)
: to score an ace against (an opponent in tennis)
US : to score an ace on (a hole in golf)