21B3

21B3 is a designation used in multiple fields to label a particular item, model, or symbol. There is no single, universally defined meaning for the term; its interpretation depends on the context and domain.

In science and medicine, alphanumeric codes frequently identify genes, proteins, plasmids, antibodies, or experimental samples. A code such as 21B3 may appear in catalog listings, publications, or laboratory records. Determining its exact reference requires additional context such as the organism, the vendor, or the genetic locus.

In engineering and consumer electronics, 21B3 can function as a model number or part identifier. It may appear on product labels, manuals, or bills of materials.

In transportation, manufacturing, or software packaging, the code could denote a variant, revision, or batch.

Identifying 21B3 requires checking source metadata: who issued it, what product line it belongs to, and any accompanying serials or identifiers. If you provide the domain or a link to the source, a more precise explanation can be given. Disambiguation practices commonly involve searching catalog databases, manufacturer literature, or literature databases with the exact string 21B3.