* Noun: This is the most common usage, referring to a plant, especially one considered undesirable or unwanted.
* Example: "The gardener pulled out all the weeds."
* Verb: This refers to the act of removing unwanted plants.
* Example: "I spent the afternoon weeding the garden."
* Slang: This refers to marijuana.
* Example: "He was caught with a bag of weed."
To determine the correct part of speech, you need to look at the sentence and consider the context.