The phrase "wee bag" typically uses the word "wee," which is a common diminutive term in Scottish and Northern Irish English meaning "small." So, "wee bag" simply means "small bag." It can be used informally and affectionately to describe a small container or bag. Additionally, in some contexts, especially related to medical or health topics, "wee bag" may refer to a small urine collection or drainage bag used to collect urine from a catheter or incontinence device. But generally, if you hear "wee bag" in conversation, it likely just means a small bag, with "wee" adding a friendly or informal tone to the phrase. For example, someone might say "Do you want a wee bag with that?" meaning a small bag for carrying items. So in short:

• "Wee" means small or little.
• "Wee bag" means a small bag, often used casually or affectionately.
• Can also refer to a small urine collection bag in medical contexts.

This usage of "wee" creates a friendly, informal, or endearing touch to the word it modifies. For example, "wee hand," "wee drink," or "wee seat" all mean a small or little version of those things or are used affectionately.