companies

Only the countable meanings of company take this plural: business firms, military units within a battalion, fire companies, a ship's whole crew. The uncountable sense of companionship stays singular. You enjoy someone's company, never their companies. The same spelling also serves the archaic verb form, so in she companies the bereaved it is a verb, while in two companies merged it is plainly the noun.

Here an obsolete spelling vanishes. Companie and modern company form the same plural, so in an old text the plural looks entirely current, and only the singular shows the older spelling. A modern writer has nothing to choose between: the form is simply the plural of company, carrying every meaning of the ordinary noun plural.