Noticeable means easy to see, hear, or detect. When something is noticeable, it stands out enough that people can't help but notice it.

A noticeable improvement in your handwriting means anyone looking at your work can clearly see you've gotten better. A noticeable smell in the cafeteria tells you what's for lunch before you even get there. When your friend gets a noticeable haircut, it's obvious enough that people comment on it.

The word suggests something crosses a threshold from barely there to clearly present. A single degree of temperature change isn't noticeable, but a ten-degree drop definitely is. One spelling mistake in an essay might slip by, but five misspellings become noticeable.

Something can be noticeable in good ways or bad ways. A scientist celebrates when her experiment produces noticeable results. A student cringes when he makes a noticeable error during his presentation. The key is that being noticeable means others can perceive it without trying hard. When something is truly noticeable, you don't need someone to point it out, because it's already caught your attention.