n. — especially Education
the majority pronunciation of the letter Z.
Type: 2. Preservation — The pronunciation of the letter Z as zed rather than "zee" is not limited to Canadian English. It is the predominant form in Great Britain and most other Commonwealth and English-speaking countries, deriving from "zeta" in Greek. The dominant American pronunciation of the letter as "zee" was first listed in 1677 in Lye's New Spelling Book (see Casselman reference) and this form was likely solidified in American English by Noah Webster in his American Spelling Book published in 1783 and following.
"Zee" is sometimes used by Canadian children as they learn the (American) alphabet song, where the pronunciation of Z is changed from zed to "zee" in order to rhyme with a preceding letter (Chambers 2009: 202; see also the 2009 quotation). Once in school, however, their pronunciation changes back to zed in what sociolinguist William Labov would call an "age-graded change", a change that is predictable by a speaker's age. In Canadian adults, zed is by far the predominant form (see Chambers 2009). "Zee", however, is a strong but stable minority variant at about 20% across all ages and regions. While a strong tendency towards zed persists, the showing of "zee" means that statements such as those made in the 1995 and 1999 quotations are untenable over-simplifications.
See also COD-2, s.v. "zed", which is marked "Cdn & Brit.", W-3, s.v. "zed", which is marked "chiefly Brit.", AHD-5, s.v. "zed", which is marked "Chiefly British".