The word proximity means nearness or closeness. "Because of the proximity of our desks, I couldn't help but notice him cheating on the exam."
Your favorite thing about your neighborhood of attached row houses might be the proximity of your neighbors — they're really close to you. Proximity comes from the Latin proximus, "nearest," which also gives us approximate, "close to the actual." You can use this noun to talk about a physical closeness, or something that's near in time, like the proximity of the months April and May.