Sometimes 'fractional' describes something insignificant, emphasizing its smallness in a non-literal, metaphorical way. Her interest in the topic was only fractional.
Pro Tip 2/3
Not Always Literal
'Fractional' can indicate a very small part of something without referring to an exact mathematical fraction. They could only see a fractional glimmer of light in the dark room.
Pro Tip 3/3
Emphasis on Smallness
Using 'fractional' often emphasizes how surprisingly small something is. There was only a fractional difference in their ages.