Interjections

Interjections
Hi! That's an interjection. :-)
"Interjection" is a big name for a little word. Interjections are short exclamations like Oh!, Um or Ah! They have no real grammatical value but we use them quite often, usually more in speaking than in writing. When interjections are inserted into a sentence, they have no grammatical connection to the sentence. An interjection is sometimes followed by an exclamation mark (!) when written
Here are some interjections with examples:

interjection	meaning	example
ah	expressing pleasure	"Ah, that feels good."
	expressing realization	"Ah, now I understand."
	expressing resignation	"Ah well, it can't be heped."
	expressing surprise	"Ah! I've won!"
alas	expressing grief or pity	"Alas, she's dead now."
dear	expressing pity	"Oh dear! Does it hurt?"
	expressing surprise	"Dear me! That's a surprise!"
eh	asking for repetition	"It's hot today." "Eh?" "I said it's hot today."
	expressing enquiry	"What do you think of that, eh?"
	expressing surprise	"Eh! Really?"
	inviting agreement	"Let's go, eh?"
er	expressing hesitation	"Lima is the capital of...er...Peru."
hello, hullo	expressing greeting	"Hello John. How are you today?"
	expressing surprise	"Hello! My car's gone!"
hey	calling attention	"Hey! look at that!"
	expressing surprise, joy etc	"Hey! What a good idea!"
hi	expressing greeting	"Hi! What's new?"
hmm	expressing hesitation, doubt or disagreement	"Hmm. I'm not so sure."
oh, o	expressing surprise	"Oh! You're here!"
	expressing pain	"Oh! I've got a toothache."
	expressing pleading	"Oh, please say 'yes'!"
ouch	expressing pain	"Ouch! That hurts!"
uh	expressing hesitation	"Uh...I don't know the answer to that."
uh-huh	expressing agreement	"Shall we go?" "Uh-huh."
um, umm	expressing hesitation	"85 divided by 5 is...um...17."
well	expressing surprise	"Well I never!"
	introducing a remark	"Well, what did he say?"