二者都是“一楼”的意思，区别在于ground floor是英式英语的说法，first floor是美式英语的说法。而英式英语的“二楼”叫做：first floor，美式英语则是：second floor，以此类推。
floor的用法例句：
1.Ministers took the floor to denounce the decision to suspend constitutional rule.
几位部长发言谴责暂停宪制的决定。
2.There was constant jeering and interruption from the floor.
议员席上不断有人在嘲讽和打岔.
3.He was holding a cloth that dripped pink drops upon the floor.
他正拿着一块布，布上粉红色的水滴落在地板上。
4.She had been sitting with her knitting at her fourth-floor window.
她那时正坐在5楼的窗前织东西。
5.Bob slid from his chair and lay prone on the floor.
鲍勃从椅子上滑下来，趴在了地板上。
6.The sand on the floor scrunched under our feet.
地板上的沙子在我们脚下嘎吱作响。
7.The elevator creaked to a halt at the ground floor.
电梯嘎吱一声停在了一层。
8.Books are often stacked in higgledy-piggledy piles on the floor.
书本经常乱七八糟地堆在地板上。
9.A bra and a pair of briefs lay on the floor.
地板上有一个胸罩和一条短内裤。
10.On the top floor we have sleeping quarters for women and children.
我们在顶楼有供女人和孩子睡觉的地方。