A commonly misspelled word is "gauge". Not only is it written wrongly in an inappropriate context, but its meaning is also confused with the signification of the word "gage".
Let's discuss the difference between "gage" and "gauge" so that you clearly understand which word to use when and never get bothered again by a potential confusion between these two!
Gage vs. Gauge
The word "gage" stands for pledge. It is defined as a guarantee given against an obligation. It is regarded as a security, whether it is for a bet, for an organization or for a bank. At the same time, though, "gage" can also be used to express a challenge, in the sense of a fight.
Example 1: "Her father's apartment is her gage for the bank." - a gage practically serves as a guarantee for a loan.
Example 2: "Throw up your gage" - this is an expression meaning to forfeit a fight or to avoid a challenge.
The word "gauge", on the other hand, is used both as a noun and as a verb. As a verb, "gauge" refers to measuring, estimating, analyzing or evaluating dimensions. Whereas used as a noun, "gauge" stands for the actual dimension, usually a conventional, standard capacity of quantity. In addition, "gauge" can also be sometimes used as a noun referring to a measurement tool used for the measurement of fuel, oil, pressure and so on.
Example 3: "The NASA staff is trained to gauge the proximity of stars, planets and other elements of the galaxy." - used as a verb, it stands for estimating/evaluating/measuring a distance.
Example 4: "They estimated the thickness of the material to get slightly over 30 gauge." - as a noun, it often stands for the thickness or size of an element.
Example 5: "The fuel gauge was indicating some low values." - "gauge" can also refer to a measuring tool, as a noun.
When do we use "gage"?
Almost never. This word is considered obsolete in modern times and can easily be replaced by other words. So avoiding it would be the safest decision for both linguistic elegance and respect of formal vocabulary nowadays. Using "gage", anyway, is mostly appropriate in the examples discussed above, as a noun.
When do we use "gauge"?
As a verb, the word is always spelled "gauge" and refers to measuring, evaluating. This is still a usual word and can be used to express the action of measuring, the actual measurement unit or the measurement tool. It is mostly used in a formal, technical vocabulary and you should definitely use it when talking to specialists.
The confusion between these two similarly spelled words is common, though should be avoided as they represent completely different concepts. Anyway, most important to remember is that "gauge" is related to measuring aspects, while "gage" is used less and less and has a different meaning.