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What Are Name Aliases?

A Name Alias is an alternate, officially recognized name for a Unicode character. While every assigned character has a formal Name property (or a generated name like <CJK UNIFIED IDEOGRAPH-4E2D>), some characters have additional aliases for several reasons:

• Correction: The formal name contains a historical error that cannot be changed (Unicode names are immutable once published), so a corrected name is provided as a Correction alias.
• Control code names: Characters in the C0 and C1 control ranges (U+0000–U+001F, U+007F–U+009F) have formal names like NULL or no readable name at all; their familiar abbreviations (NUL, LF, CR, DEL) are registered as Control aliases.
• Abbreviations: Widely used short names like ZWSP (for ZERO WIDTH SPACE) or BOM (for BYTE ORDER MARK).
• Figments: Names that appeared in published Unicode data due to errors and were then retracted.

The BOM Case Study

One of the most instructive examples is U+FEFF:

• Formal name: ZERO WIDTH NO-BREAK SPACE
• Name alias (Abbreviation): ZWNBSP
• Name alias (Alternate): BYTE ORDER MARK
• Name alias (Abbreviation): BOM

The name ZERO WIDTH NO-BREAK SPACE is the historical, immutable name. The BOM function—indicating byte order in UTF-16/UTF-32 streams—was added later, but Unicode names cannot be changed. The alias BYTE ORDER MARK documents the actual common use.

import unicodedata

# unicodedata.name() returns the formal name only
print(unicodedata.name("\uFEFF"))
# ZERO WIDTH NO-BREAK SPACE

# unicodedata.lookup() works with both formal names and aliases
bom_by_alias = unicodedata.lookup("BYTE ORDER MARK")
print(f"U+{ord(bom_by_alias):04X}")
# U+FEFF

# Control character aliases
nul = unicodedata.lookup("NUL")          # U+0000
cr  = unicodedata.lookup("CARRIAGE RETURN")  # U+000D
lf  = unicodedata.lookup("LINE FEED")    # U+000A
print(ord(nul), ord(cr), ord(lf))
# 0 13 10

Alias Types

The Unicode Standard defines five alias types:

Quick Facts