Interjection, << `ihn` tuhr JEHK shuhn, >> is a word used in a sentence as an independent element, grammatically unrelated to the other words. The term comes from a Latin word meaning thrown in between. The interjection has no identifiable features of form, but it may be described by its use.
Interjections generally express some kind of emotion, such as pain, sorrow, anger, or relief. Many are sound words, such as ouch, whew, and oh. Most swearwords are interjections, as are the polite forms related to swearwords, such as darn, gosh, and heck. But in the expression “That’s a darned shame,” darned is a modifier, not an interjection.
Interjections serve as fillers and attention-getters. Oh, well, and why are basically filler words in such expressions as “Oh, I don’t think so,” “Well, we might try,” and “Why, that’s too bad.” Expressions like say, look, and hey there are either signals to listen or forms of address, as in “Say, I have an idea” or “Hey there, what’s going on?”
In writing, exclamation marks sometimes follow interjections. More often, a comma separates an interjection from the words that follow.