play、from和welcome之间是否存在类同关系？

"Play", "From", and "Welcome" are all common English words that refer to starting something or being introduced to something. They share the root word "plea" and have similar connotations of beginning or introduction.

play和from和welcome都是同类词吗？

play是动词，玩耍，游戏的意思，后边可以加名词，play the football,踢足球。
from是介词，从…来，出自…，from China,来自中国。
welcome是动词，欢迎的意思，Welcome to home,欢迎回家。
所以从它们的词性和词义来看，完全不同，在句子中的充当成分也不相同。