Which word is used incorrectly in the following sentence? The procedure for giving injections were explained thoroughly to the student nurses.

In the sentence provided, the word "were" is used incorrectly because it does not agree in number with the subject of the sentence, "the procedure." The subject "procedure" is singular, so the correct verb form should also be singular to ensure subject-verb agreement. Therefore, the sentence should read: "The procedure for giving injections was explained thoroughly to the student nurses." This change aligns the singular subject with the appropriate singular verb "was," providing grammatical consistency in the sentence. The other words in the sentence—"thoroughly," "procedure," and "student"—are used correctly in context.