In England, what we call daddy-long-legs are actually six legged insects, also called crane flies. And, confusingly, also called water spiders though they are not spiders and the adults do not live in water. A few larval forms do live in water.
In the USA, daddy-long-legs refers to a harvestman, an 8 legged arachnid as has been said. End of lecture
I studied zoology light years ago!