
Based on the premise that
"lumen" sounds like "LEMON"?
The Big Bang Theory Season 12, Episode 14

From now on, "frog" is me, "sandwich"
means you, and "LEMON" means rocket.
The Big Bang Theory Season 6, Episode 3

A LEMON one... or any of them.
Game of Thrones Season 1, Episode 9

He knew you liked LEMON cakes.
Game of Thrones Season 4, Episode 5

Oh, do you--? I used to squeeze
LEMON juice in my hair.
Breaking Bad Season 5, Episode 8