Lemon – le citron
(Pronounced seet-rohn (but you barely pronounce the 'n'))
To remember that Lemon is pronounced seet-rohn (citron) in French, use the following mnemonic:
The lemon drove a Citroen (citron).

Citron is masculine, so it's le citron. Imagine the early learner taking a bite out of a lemon and pulling a face.

Examples of citron (lemon) in a sentence
J'aime ajouter un peu de jus de citron dans mon thé.
(I like to add a little lemon juice in my tea.)
La tarte au citron meringuée est mon dessert préféré.
(Lemon meringue pie is my favorite dessert.)
Il a ajouté une touche de citron à la salade.
(He added a touch of lemon to the salad.)