1 n. — Sports
a level of sport for children up to 10, usually 9-10 in hockey.
Type: 3. Semantic Change — This meaning is an extension of the meaning of atom as 'any very small object (without the implication that it is a particle of something else); a (relatively) tiny person or thing' (OED-3, s.v. "atom" (9a)). The age range varies from sport to sport and over time, see, e.g. the quotations from 1968 (7-10) and 1989 (under 8), or the 1998 quotation in meaning 2 (9).
See also COD-2, s.v. "atom" (2a), which is marked "Cdn", ITP Nelson, s.v. "atom" (4), which is marked "Hockey".
See also: peewee bantam espoir novice midget mosquito hockey mom hockey dad
- 1960  [Heading] Toronto Hockey League
(Levels Listed)
Atom
Peewee
Minor-Bantam
Bantam
Minor-Midget
Midget
- 1968  ATOM DIVISION -- 7-10 Years 
- 1979  In Atom division Atom Motors and Ocean Cement met, the final score was a 2-2 tie. 
- 1981  Although there is no bodychecking permitted at this age level, defenceman Lokas Loukidis said he found it more difficult to stop the older players because "they have different moves than atom players in our league." 
- 1989  "When I first began coaching at the atom level, I did it because I honestly believed that football was a great game for youngsters. 
- 1989  Race results are as follows: Atom Girls (7 yrs. & under) 1 km 
- 1997  Included in the weekend of festivities will be the fifth-annual North American Native Minor Hockey Tournament of Champions, with 12 teams per division, and entries at the squirt, novice, atom, peewee, bantam and midget levels.
- 2003  Hockey dad on trial for death threat: Montreal police officer yelled "I'll kill him" to referee of atom game, witnesses testify.
2 n. — Sports
a player in such a division.
Type: 3. Semantic Change — See meaning 1.
See also COD-2, s.v. "atom" (2b), which is marked "Cdn".