To truncate something means to cut it short or chop off its end, making it shorter than it was originally meant to be. When you truncate a story, you end it abruptly before reaching its natural conclusion. When a builder truncates a wooden beam, they saw off part of its length to make it fit.

The word often suggests that something was cut off in a way that feels incomplete or unfinished. A truncated conversation is one that gets interrupted before you've said everything you wanted to say. In mathematics, a truncated decimal is one where extra digits have been removed: instead of writing 3.14159, you might truncate it to 3.14.

You might truncate a long book report to fit a page limit, cutting paragraphs to make it shorter. Scientists sometimes truncate large numbers to make them easier to work with. The key idea is that truncation removes part of something, usually from the end, leaving what remains shorter or less complete than the original.