tard et tôt

 Tard:

Meaning: "Tard" means "late" or "lateness."

Usage: It indicates a time that is later than expected or desired.

Example: "Je suis arrivé tard à la réunion." (I arrived late to the meeting.) 

In this example, "tard" emphasizes that the person arrived at the meeting after the expected or scheduled time.

Tôt:

Meaning: "Tôt" means "early" or "earliness."

Usage: It indicates a time that is earlier than expected or desired.

Example: "Elle se lève tôt le matin." (She wakes up early in the morning.) 

Here, "tôt" highlights that the person wakes up at a time that is earlier than typical or necessary for many people.

To summarize, "tard" refers to being late or lateness, while "tôt" refers to being early or earliness. 

They both provide information about time relative to expectations or norms, but in opposite directions.