A lump is a solid chunk or mass of something, usually with an irregular shape. When you mix flour and water carelessly, you might end up with lumps in your batter instead of a smooth mixture. A lump of clay sits heavy in your hand, ready to be shaped. You might find a lump of coal in a Christmas stocking, or discover a lump of rock candy at the bottom of your tea.

The word also describes swellings or bumps, like when you bonk your head and feel a lump forming, or when a doctor checks for lumps during an examination.

As a verb, to lump things together means to group them as if they're all the same, even when they're different. If your teacher lumps all the students who forgot their homework into the same category, she's treating everyone the same way, regardless of their individual reasons.

When someone tells you to “like it or lump it,” they mean you have to accept the situation whether you want to or not. There's no third option and no negotiating. It's their way of saying the decision is final.

A lump sum is a single payment of the whole amount at once, rather than smaller payments spread out over time.