momentarily
adv.for a very short time, or very soon. You use it when something happens quickly or will happen in just a second.
adv.for a brief period of time; alternatively, in a very short while. The latter sense is particularly common in North American English.
“The power went out momentarily during the storm.”
“Please hold the line; the operator will be with you momentarily to assist with your request.”
“The speaker paused momentarily to gather his thoughts before addressing the most controversial aspect of the new policy proposal.”
In British English, it primarily means 'for a short time'; in American English, it frequently means 'very soon'.
Momentarily is an adverb and should not be preceded by a preposition like 'for' when indicating when something will happen.
“A large cloud momentarily covered the sun entirely, but when it cleared ahead of the maximum eclipse a cheer erupted from the crowd.”
“This means that users often momentarily remove the glasses in order to look at the solar disk directly, without protection, which exposes their eyes solar and ultraviolet radiation.”
From momentary + -ly.
Etymology adapted from Wiktionary, available under CC BY-SA 4.0.