Meaning:
age bracket 
n.
a group people having approximately the same age
rack Idiom, Proverb
all it's cracked up to be
as good as the ads say, live up to the reports The new computer isn't all it's cracked up to be. It's not so hot.
at the crack of dawn
at the first sign of light, at first light At the crack of dawn he would rise, wash and go for a walk.
crack a book
study, read a textbook Sean passed that exam without cracking a book.
crack a joke
tell a joke, say a funny word or phrase Please be serious. Don't crack jokes or laugh at us.
crack down on
stop, not permit, not allow The police began to crack down on speeders in the school zones.
crack me up
make me laugh hard, split a gut Robin Williams cracks me up when he tells a story.
crack of dawn
(See at the crack of dawn)
crack shot/salesman etc.
a person who is highly skilled at shooting etc. Marvin has developed into a crack salesman. He's excellent.
crack the line-up
earn a place on a team, make the team He's a good basketball player, but can he crack the line-up?
crack this case
solve a crime, discover who is guilty "David will crack this case; he's a thorough investigator."
crack under the strain
become irrational or hysterical due to strain, around the bend Mother was a strong person. She never cracked under the strain of raising ten children.
cracked
crazy, nuts, wacko He must be cracked. He mailed a letter to himself.
crackers
crazy, bonkers, nuts Don't worry about me. I've been crackers all my life.
crackpot
a person who is strange or weird, wacko Some crackpot wrote a letter to him threatening his family.
crackup
collision, crash Drinking and driving causes a lot of crackups.
fall through the cracks
not be included, leave out These children fell through the cracks. They didn't learn to read.
fast track
the quickest route or path, short cut There is no fast track to success in the field of photography.
first crack at
first turn, first chance to do it I want first crack at solving the problem. I want to try first.
get cracking
hurry up, start moving fast, get started We will have to get cracking on this work if we want to finish it before dinner.
go to rack and ruin
reach a very bad state of repair The building has gone to rack and ruin since the new owners took over.
hard nut to crack
something or someone difficult to understand or do He is a very serious person and is a very hard nut to crack.
inside track
an advantage, shortest distance around a racetrack I think that he has the inside track on getting the new job at the computer company.
keep track
check, count Keep track of the time you work at the computer. Keep a record.
keep track of
maintain a record Please carefully keep track of your expenses during the trip.
keep you on track
tell you what to do, remind you of the topic The instructor will help to keep us on track. She'll remind us.
lose track
forget how many you have, lose count He tried to count the number of birds, but he soon lost track.
lose track of
lose contact with someone (or something) I
make tracks
hurry, move quickly, vamoose We better make tracks or we'll be late for dinner.
not all it's cracked up...
(See all it's cracked up to be)
off the beaten track
not on the main road, out of the way I like to explore places that are off the beaten track - wild places.
on track
in the right direction, on the rails After a few problems, our project is back on track.
one-track mind
thinking about only one thing He has a one-track mind. All he thinks about is money.
rack my brain
think hard, try to remember I've racked my brain, but I can't remember where I saw that man.
rack one
try one's best to think, make a great mental effort I racked my brain for over an hour to try and figure out what to do about the problem with the new computer.try hard to think or remember something I have been racking my brains all day trying to remember his name.
rack up
compile, increase, build up, run up He racked up a lot of points with his first hand of cribbage.
stop you in your tracks
cause you to stop, prevent you from going further You know what will stop you dead in your tracks? A bear, that's what.
take a crack at
try, attempt Have you decided to take a crack at the entrance exam in June?
the crack of dawn
(See at the crack of dawn)
the inside track
being close to the person who has power, Bob's your uncle If your uncle works at Sears, you should have the inside track on the new job in Men's Wear.
track down
search for I have been trying to track down an old Beatles album for many months.
track record
list of achievements, summary of career work Lou's track record is excellent. She was top seller last year.
be smokin' crack rock
doing something stupid, (used as an excuse for doing something really stupid usually in front of someone else) "I didn't delete that file; I'm just smokin' crack rock."
crack
1. synthetic drug, extremely addictive
2. the vagina, Particularly vulgar expression
3. between the buttocks
4. (As the crack) the situation, the news, the gossip; from the Irish craic:"So what's the crack with this arguement you and Sonya have been having?"
5. see also what's crackin
crack a brew
to open a beer:"Crack another 40, smoke some kill" -- Schoolly D. (Smoke some kill)
crack snacker
a lesbian
crack up
1. to breakdown with laughter
2. to mentally breakdown
crackass
something exceptionally below standard or unacceptable:"What kind of a crackass statement was that?!? Her crackass boyfriend came to the formal in cut-offs"
cracked out
1. acting like a crackhead;
2. crazy; irrational
cracker
a derogatory term for a white person
crackhead
1. someone who just isn't all there; someone who does stupid things:"You hear Johnny jumped off his roof? Yeah, he's such a crackhead!"
2. an addict of "crack" (freebased cocaine)