From WordNet (r) 3.0 (2006) [wn]:
yoghurt
n 1: a custard-like food made from curdled milk [syn: yogurt,
yoghurt, yoghourt]
From The Collaborative International Dictionary of English v.0.48 [gcide]:
yoghurt \yo"ghurt\, yoghourt \yo"ghourt\, yoghourt \yo"ghourt\
n.
custardlike food made from curdled milk.
[WordNet 1.5]