I've usually seen in my little Mandarin learning experience, that when people express wait, they usually use 等. However, I just noticed the following phrase in Sina Weibo:
请稍候...
I know 请 means please, and I looked up in my dictionary, that 稍 is a little and 候 is wait. So the sentence seems to express please wait a little..., which is fine in the context (I tried reloading the data, for your information).
So what's the difference between 等 and 候?
None. They are synonyms, although they also have separate different meanings.
稍等 = 稍候 = wait a minute.
等候 = 等 = 候, although 候 is rarely used as a single character with this meaning.
There is no differences between 等 and 候. Both means "to wait". You can also put them together as a word 等候, with the same meaning - to wait.
However, 候 sounds like the usage in classical Chinese (archaic Chinese), and therefore rarely use as only one single character in modern Chinese.
For the purpose of stating "please wait", 等 and 候 both mean the "to wait".
However they each have other meanings in different context. For example, 等 also means "level" (as in 等級, 等地). 候 also means "to serve" (as in 伺候).
We say“我等你”. It means"I wait for you". But we don't say“我候你”
