ジャム
ジャム · jamu · JLPT N4 · noun
jam
🍓🍯 jamu = English jam + a trailing u; a loanword in katakana
ジャム is borrowed straight from English jam. Japanese syllables cannot end in m, so a u is added: ja-mu. Katakana spelling flags it as a foreign loanword, so say jam, tack on a soft u, and you have it.