Sens:
13th generation 
treizième génération, génération née entre 1961 et 1681 (appelée ainsi du fait qu'elle soit identifiée comme la 13ème génération après l'établissement des Etats-Unis)
en Idiome
a bit off/a bit mental
not rational, unbalanced, one brick short Kate talks to the birds. Do you think she's a bit off?
a budding genius
a child who appears to be very intelligent "The newspaper described Pam as ""a budding genius"" on the violin."
a bun in the oven
pregnant, expecting a baby Mabel has a bun in the oven. The baby's due in April.
a chicken in every pot
enough food for every family No one will be hungry if there's a chicken in every pot.
a different kettle of fish
different, not the same A cult is not a religion. A cult is a different kettle of fish entirely.
a dime a dozen
very cheap, low priced, dirt cheap He can remember when eggs were cheap - a dime a dozen.
a golden opportunity
a good chance to succeed, a good investment The Royal Hotel is for sale. What a golden opportunity!
a horse of a different color
a different matter, a separate issue If he wants to buy the land, that's a horse of a different color.
a mental block
a problem with learning a subject or concept I have a mental block when I try to do algebra. I can't think.
a penny for your thoughts
tell me what you are thinking about "When I'm quiet, she will say, ""A penny for your thoughts."""
a penny pincher
a person who spends carefully, a thrifty person He used to be a penny pincher, but now he spends freely.
a pretty penny
a lot of money, a high price I bet she paid a pretty penny for that coat. It looks expensive.
a send-up
a mockery or satire, a takeoff on The speaker did a send-up of the the way Canadians talk.
a sucker for punishment
one who allows himself to be hurt or blamed If I accept blame for a team loss, I'm a sucker for punishment.
a token gesture
a small sign of thanks or recognition To thank us, they put our names in the paper - a token gesture.
a tower of strength
a person who helps you during a crisis, a brick When my parents were killed in an accident, Harry was a tower of strength to me.
a word to the wise is sufficient
a wise person understands when he hears a key word I can't discuss the plan, but a word to the wise is sufficient: progress.
absence makes the heart grow fonder
when friends are apart they like each other more When she's away I'm very lonely. Absence does make the heart grow fonder.
absent-minded
forgetful Our neighbor is very absent-minded and is always getting locked out of his house.
all of a sudden
suddenly, without advance warning All of a sudden it became cloudy and began to rain.
all's well that ends well
a happy ending is the most important thing, the end justifies... Although we argued and fought, we are happy with the result. All's well that ends well!
an even keel
good balance, stability We need a steady manager, one who can keep an even keel.
an ounce of prevention is worth a pound of cure
prevent a problem so you don't have to solve it, a stitch in time... Forest fires deserve an ounce of prevention: public education in campfire safety.
anal retentive
too concerned with detail, pedantic Amy is anal retentive. She writes down everything the teacher says.
and then some
and much more besides.
around the bend
crazy or insane, off your rocker If I had to listen to that noise all the time, I'd go around the bend.
as scarce as hen's teeth
rare, uncommon, not many of them Country doctors are as scarce as hen's teeth.
at a moment's notice
with little warning, on short notice We may call you at a moment's notice - whenever we need help.
at loose ends
disorganized, unable to concentrate I was at loose ends when the kids were fighting. I couldn't think.
at my wits' end
very tired and nervous, at the end of my rope After a wedding and a funeral she was at her wits' end.
at sixes and sevens
in a state of confusion Everyone was at sixes and sevens after the announcement that the company was going out of business.
at the eleventh hour
" at the last minute; almost too late. "
at the end of my rope/ at the end of my tether
losing control of myself, losing patience (see lose patience) Babysitting five kids, I was at the end of my rope.
at the end of one
at the limit of one
attend to someone
take care or deal with someone The doctor attended to the other patient before he got to my mother.
be-all, end-all
trying to be too great, world beater The new manager thinks he's the greatest - the be-all, end-all.
been around
experienced, not naive, wasn't born yesterday "Margo's been around; she can work with the convicts."
been had
cheated, swindled, taken in If he paid a hundred dollars for that radio, he's been had.
behind the scenes
out of sight, unnoticed, unsung hero This organization has many people who work behind the scenes helping us to succeed.
bend over backwards
do anything to help, try to please, go the extra mile They'll bend over backwards to find a room for you. They give excellent service.
bend over backwards to do something
try very hard If I can, I will bend over backwards to help you get a promotion in the company.
bend the rules
change the rules to help, look the other way Ed won't accept late reports. He won't bend the rules.
bend your ear
ask you to listen, buttonhole you Carl, can I bend your ear for a minute? I have some news.
bend your elbow
drink beer or liquor, tip a few Your eyes look red and tired. Bend your elbow last night?
benefit of the doubt
(See the benefit of the doubt)
bent out of shape
needlessly worried about something.
between a rock and a hard place
in a difficult position, making a difficult choice, Sophie's choice If I told the truth, I would lose my friend. I was between a rock and a hard place.
between sixes and sevens
(See at sixes and sevens)
between the devil and the deep blue sea
in a difficult position, no place to go, between a rock..., Sophie's choice "If he ran, they would shoot him; if he stayed in the shop, the gas would kill him. He was between the devil and the deep blue sea."
betwixt and between
not able to choose one or the other, ambivalent Which should I choose - PC or Mac? I'm betwixt and between.