I. J¹ , j /dʒeɪ/ noun (plural J’s, j’s) [uncountable and countable]
the tenth letter of the English alphabet

[TahlilGaran] Dictionary of Contemporary English ▲

II. J²
the written abbreviation of joule or joules

[TahlilGaran] Dictionary of Contemporary English ▲

J-17 /ˌdʒeɪ ˌsevənˈtiːn/ trademark
a British magazine for teenage girls, formerly called Just Seventeen, which contained pictures and articles about fashion, health, music, boys etc, and answers to readers' questions about personal problems. It stopped being published in 2004.

[TahlilGaran] Dictionary of Contemporary English ▲