Midway is what is halfway, represents a moderate attitude and with balance between two parts.
The two words form a compound noun, and this type of semantic unit must be hyphenated. Therefore, the correct spelling in Portuguese is a middle term and not a middle term.
If there are two opposite poles, two extremes, the in-between would be what is situated in the middle, between one and the other.
It is understood as something moderate, has to do with balance or even a measured attitude. For example: "there must be a middle ground between formal and informal behavior in the routine of the work environment".
Coming to a compromise is reach consensus between two opposite parts.
In English, in the sense of agreement, it is translated by compromise. In other uses, the terms middle course or middle way, and still half term.
It also indicates indecision. Using compromises is not saying something concrete, not wanting to commit to either side. An expression often used in the Political environment, for example: "the councilor's speech remained in the middle. Neither agreed with the bench, nor disagreed with the mayor".
Some synonyms for in-between are moderation, restraint or half.
Middle Term Plural
The plural of halfway is halfway. For the expression is made up of a numeral, middle, and a noun, term. As a rule, this type of construction must agree with all the elements that compose it.
Aristotle's Midway
Aristotle's middle ground is a doctrine created by the Greek philosopher. The middle ground for the thinker would be the ideal state of life in society, where extremes are reprehensible (they are vices), and one must live to seek balance.