Ḫāʾ, Khāʾ, or Xe (خ, transliterated as ḫ (DIN-31635), ḵ (Hans Wehr), kh (ALA-LC) or ẖ (ISO 233)) is one of the six letters the Arabic alphabet added to the twenty-two inherited from the Phoenician alphabet (the others being ṯāʼ, ḏāl, ḍād, ẓāʼ, ġayn). It is based on the ḥāʾ ح. It is related to the Ancient North Arabian 𐪍, South Arabian 𐩭, and Ge'ez ኀ.
It represents the sound [x] or [χ] in Modern Standard Arabic. The pronunciation of خ is very similar to German, Irish, and Polish unpalatalised "ch", Russian х (Cyrillic Kha), Greek χ and Peninsular Spanish and Southern Cone "j". In name and shape, it is a variant of ḥāʾ. South Semitic also kept the phoneme separate, and it appears as South Arabian 
, Ge'ez Ḫarm ኀ. Its numerical value is 600 (see Abjad numerals). In most European languages, it is mostly romanized as the digraph kh.