FoldList

FoldList[f,x,{a,b,…}] gives {x,f[x,a],f[f[x,a],b],…}. 

FoldList[f,{a,b,c,…}] gives {a,f[a,b],f[f[a,b],c],…}.

FoldList[f] represents an operator form of FoldList that can be applied to expressions. 

Please visit the official Wolfram Language Reference for more details and examples on core symbols.