Definitions of pick up:

• verb:   recieve (perceptual input)

  Example: "Pick up a signal"

• verb:   buy casually or spontaneously
• verb:   get in addition, as an increase
• verb:   meet someone for sexual purposes

  Example: "He always tries to pick up girls in bars"

• verb:   lift out or reflect from a background
• verb:   take up by hand
• verb:   give a passenger or a hitchhiker a lift
• verb:   take and lift upward
• verb:   perceive with the senses quickly, suddenly, or momentarily
• verb:   gather or collect

  Example: "They pick up our trash twice a week"

• verb:   eat by pecking at, like a bird
• verb:   get better
• verb:   gain or regain energy
• verb:   fill with high spirits; fill with optimism
• verb:   get to know or become aware of, usually accidentally
• verb:   take into custody