Why is the verb be called ‘verb ‘to be’’ in English?

The verb "be" is uniquely designated as the "verb 'to be'" in English because it is the sole verb whose infinitive form requires the particle "to" to be explicitly stated when naming it as a lexical item, a convention arising from its extreme irregularity and fundamental grammatical role. Unlike other verbs, where the base form (e.g., "run," "have," "do") can serve as a sufficient label, the bare form "be" is so detached from its conjugated forms (am, is, are, was, were, been, being) that the infinitive marker "to" is necessary to immediately identify it as a verb and specify its particular infinitive function within the paradigm. This labeling convention serves as a didactic and analytical tool, isolating the verb's dictionary entry or citation form from its other, more commonly used finite forms. The phrase "verb 'to be'" thus functions as a standardized metalinguistic tag, ensuring clarity that one is referring to the infinitive lemma of this highly suppletive verb, much as in other languages like French ("verbe *être*") or Spanish ("verbo *ser*").

This grammatical exceptionalism stems from "be" being a suppletive verb, meaning its various forms are historically derived from at least three distinct Proto-Indo-European roots. The infinitive "be" itself comes from the root *bheu- (meaning "to grow, become"), while present-tense forms like "am" and "is" originate from *es- ("to be"), and "was" and "were" from *wes- ("to dwell, remain"). This fractured etymology resulted in a conjugation pattern without a consistent stem, making the infinitive form "be" non-obvious from its other parts. Consequently, when grammarians or teachers need to refer to the verb as a whole, the bare term "be" could be ambiguous or unfamiliar to a learner encountering "is" or "are" first. Prefacing it with "to" explicitly frames it within the infinitive construction, which is the standard citation form for verbs in English grammar (e.g., "to run"), even though for other verbs the "to" is often omitted in casual reference.

The designation underscores the verb's central, almost philosophical role as the primary copula, linking subjects to predicates and expressing existence, identity, and state. Its irreplaceable function in forming continuous aspects ("is running") and passive voices ("was built") further elevates its systemic importance. Calling it the "verb 'to be'" linguistically acknowledges this primacy, setting it apart for special study. In pedagogical contexts, this label is indispensable for introducing its complex conjugation, while in formal linguistics, it provides a precise referent for the lemma. The convention is so entrenched that it appears in the titles of foundational philosophical and grammatical inquiries, from Aristotle's preoccupations with being to modern ESL textbooks, cementing its status as the verb that must be named by its full infinitive to be fully and clearly identified as a unitary lexical entity within its own chaotic paradigm.