1) ASSURE/ENSURE/INSURE
To “assure” a person of something is to make him or her confident of it. According to Associated Press style, to “ensure” that something happens is to make certain that it does, and to “insure” is to issue an insurance policy. Other authorities, however, consider “ensure” and “insure” interchangeable. To please conservatives, make the distinction. However, it is worth noting that in older usage these spellings were not clearly distinguished.
European “life assurance” companies take the position that all policy-holders are mortal and someone will definitely collect, thus assuring heirs of some income. American companies tend to go with “insurance” for coverage of life as well as of fire, theft, etc.
2) ASTERICK / ASTERISK
Some people not only spell this word without its second S, they say it that way too. It comes from Greek asteriskos: “little star.” Tisk, tisk, remember the “-isk”; “asterick” is icky.
3) AS OF YET / YET
“As of yet” is a windy and pretentious substitute for plain old English “yet” or “as yet,” an unjustified extension of the pattern in sentences like “as of Friday the 27th of May.”
4) AT ALL
Some of us are irritated when a grocery checker asks “Do you want any help out with that at all?” “At all” is traditionally used in negative contexts: “Can’t you give me any help at all?” The current pattern of using the phrase in positive offers of help unintentionally suggests aid reluctantly given or minimal in extent. As a way of making yourself sound less polite than you intend, it ranks right up there with “no problem” instead of “you’re welcome.”
5) ATM machine / ATM
“ATM” means “Automated Teller Machine,” so if you say “ATM machine” you are really saying, “Automated Teller Machine machine.”