noun

• An edible plant, Lactuca sativa and its close relatives, having a head of green and/or purple leaves.
• (uncountable) The leaves of the lettuce plant, eaten as a vegetable; as a dish often mixed with other ingredients, dressing etc.
• (uncountable, US, slang) United States paper currency; dollars.
• A strong yellow-green colour, like that of lettuce (also called lettuce green).
• (uncountable, slang) weed or marijuana
• (uncountable, slang) long hair, as worn by an exemplar of bro culture