So much of it depends on where and when we are talking, for sure. The CTBUH (
https://www.ctbuh.org/resource/height) suggests that they are the arbiters of these classifications, and define it along the lines of 50m as 'tall building', what would generally be called a high-rise, and 300m for a supertall. Definitely 50m is too short for a 'skyscraper' and 300m too large, so it's up in the air (pun) if a skyscraper starts at 100m, 150m, or 200m, though I suppose 150m is probably more generally accepted.
Speaking for myself, I would consider 50m too short for a true high-rise, and 35m definitely too short. SSP is a little crazy for having the forums be split from 35m for high-rises and then nothing up to supertalls at 300m. SSC has high-rise at 100m and skyscraper at 200m like my previous post, though I don't think either forum follows anything official.