a0a

A0A is a designation that appears in several distinct contexts, and its meaning depends on the specific system in which it is used. It is not tied to a single concept but rather serves as a short code that appears in different domains such as geography and data annotation.

In the Canadian postal system, A0A is a forward sortation area prefix used for Newfoundland and Labrador. The first character A indicates Newfoundland and Labrador, and the subsequent characters refine the regional delivery area. Mail addressed with a code beginning with A0A is routed to rural or smaller communities within this part of the province. The standard postal code format in Canada combines letters and digits in the pattern letter-digit-letter space digit-letter-digit, and A0A forms the initial three-character block of many Newfoundland and Labrador codes.

In bioinformatics and protein data resources, A0A is a prefix used in UniProt accession numbers for protein sequences that originate from automated, high-throughput annotation pipelines. Entries beginning with A0A are typically unreviewed or predicted proteins from genomes or metagenomic projects. This prefix helps distinguish automatically generated entries from those that have been manually curated, and it is common across many microorganisms and environmental samples.

Beyond these uses, A0A may appear as an acronym or code in other, less standardized contexts, where its interpretation must be inferred from domain-specific conventions. The term thus functions as a multi-sense identifier rather than a single, universal concept.