A dot is a very small round mark, for example one that is used as the top part of the letter 'i', as a full stop, or as a decimal point.

You can refer to something that you can see in the distance and that looks like a small round mark as a dot .

When things dot a place or an area, they are scattered or spread all over it.

If you arrive somewhere or do something on the dot, you arrive there or do it at exactly the time that you were supposed to.

If you say that someone dots the i's and crosses the t's, you mean that they pay great attention to every small detail in a task; often used to express your annoyance because such detailed work seems unnecessary and takes a very long time.

The year dot is used to mean a very long time ago.