Q:

Is this an actual phrase, "Sao Wei Deng Yi Xia" (please wait a moment)?

So I learned most of my Chinese through speaking, and I swear (especially in a service setting), people say something like:

"Sao Wei Deng Yi Xia"

等一下 is obvious, but I have not been able to find anything in the dictionary for this term, "Sao Wei"
Have I been hearing people wrong all of these years? Does anybody know the two characters I'm talking about?

A:

稍微等一下
MDBG

稍微
shāo​wēi​
a little bit
HSK 4

Here's a more detailed entry from Tuttle

稍微
[comp: 稍 slight + 微 tiny]
ADV
slightly, just a little bit
你能不能把电视机的声音开得稍微大一点? 
  Nǐ néng bu néng bǎ diànshìjī de shēngyin kāi de shāowēi dà yìdiǎn?
  Could you turn the TV up a bit? 
我稍微有点儿头疼, 休息一会儿就会好的。 
  Wǒ shāowēi yǒu diǎnr tóuténg, xiūxi yíhuìr jiù huì hǎo de.
  I've a slight headache. I'll be all right after a short rest. 

MoE's entry for 等一下 has the following example sentence:

如：「吳醫師馬上就會來為您診斷病情，請您稍微等一下。」

Taiwan's Ministry of Education certainly thinks that 稍微等一下 is a common phrase.

