The Cantonese name 油炸鬼 is oil fried ghost (油 is oil, 炸 is deep-fried, and 鬼 is ghost), so there's a story behind that.
The Mandarin name just consists of 油, which is oil, and 條, which is strip (like bacon strip), so 油條 is oil strip.
Ordering
條 is also the classifier for long thin items, so for example to order one strip of fried dough, you'd specify in Cantonese 一條油炸鬼 (yāt tíu yàuh ja gwái) one strip of oil deep-fried ghost or ,somewhat redundantly in Mandarin, 一條油條 (yī tiáo yóu tiáo) one strip of oil strip.
But typically, in a restaurant at least, multiple strips will be served on a plate, in which case you'd order 一碟油炸鬼 (in Cantonese, yāt dihp yàuh ja gwái) one plate of deep-fried ghosts.
A stick of deep-fried dough, basically a long doughnut, listed variously in English as Chinese cruller, Chinese doughnut, Chinese churro (pretty similar), by the Mandarin pronunciation youtiao, and, a directly translation of the Mandarin name), oil stick.
Typically served at breakfast with congee or soy milk, sometimes cut into short segments for convenience when serving.