Dictionary:

pot²

  (pŏt)

Marijuana.

[Origin unknown.]

Slang for marijuana. See controlled substance [cannabis].

The noun has 10 meanings:

Meaning #1: metal or earthenware cooking vessel that is usually round and deep; often has a handle and lid

Meaning #2: a plumbing fixture for defecation and urination
  Synonyms: toilet, can, commode, crapper, potty, stool, throne

Meaning #3: the quantity contained in a pot
  Synonym: potful

Meaning #4: a container in which plants are cultivated
  Synonym: flowerpot

Meaning #5: (often followed by `of') a large number or amount or extent
  Synonyms: batch, deal, flock, good deal, great deal, hatful, heap, lot, mass, mess, mickle, mint, muckle, peck, pile, plenty, quite a little, raft, sight, slew, spate, stack, tidy sum, wad, whole lot, whole slew

Meaning #6: the cumulative stake in a game (such as poker)
  Synonyms: jackpot, kitty

Meaning #7: a strong-smelling plant from whose dried leaves a number of euphoriant and hallucinogenic drugs are prepared
  Synonyms: marijuana, marihuana, ganja, grass, dope, weed, gage, sess, sens, skunk, Mary-Jane, Cannabis sativa

Meaning #8: (informal) slang terms for a paunch
  Synonyms: potbelly, bay window, corporation, tummy

Meaning #9: a resistor with three terminals, the third being an adjustable center terminal; used to adjust voltages in radios and TV sets
  Synonym: potentiometer

Meaning #10: a soft drug consisting of the dried leaves of the hemp plant; smoked or chewed for euphoric effect
  Synonyms: cannabis, marijuana, ganja, grass, marihuana, dope, weed, gage, sess, sens, smoke, skunk, Mary Jane

The verb pot has one meaning:

Meaning #1: plant in a pot