in a relative manner; by comparison to something else
"the situation is relatively calm now"
Proportionally, in relation to some larger scale thing.
"The $50 fee seems steep for a single copy, but it is relatively small compared to the annual membership cost of thousands of dollars."
In plain English: Relatively means something is compared to other things nearby rather than being judged on its own.
"The weather is relatively warm for this time of year."
Usage: Use relatively when describing something as significant only compared to another specific standard or group rather than absolutely. Avoid using it if you mean the word itself is large without any comparison needed.
The word relatively comes from adding the suffix -ly to the adjective relative. It entered English by combining these two elements to form an adverb meaning "in a relative manner."