Alternate, opposite, or whorled are all terms for various types of leaf arrangements on a stem, which is also known as PHYLLOTAXY.
Plants with alternate leaves have a single leaf at each node.
Plants with whorled leaves have 3 or more leaves around the stem at each node.
So thats whats going on here..
"WHORLED" = 3 segments at a node. "PHYLLOTAXY" = arrangement of leaves around a stem. <(DUMBED VERSION)