English forms that are no longer in use and not usually recognized by native speakers, but still sometimes found in older literature; and serve as alternative forms of the same terms in general use.

To categorize into this category, use {{obsolete form of|en|...}} or {{obsolete spelling of|en|...}}.

If the term is not merely a variant (alternative form) of a term in general use, it should be placed in [[Category:English obsolete terms]] instead; to do this, use {{tlb|en|obsolete}} (template tlb, not lb), which should typically be placed next to the headword. If only some senses of the term are obsolete, it should be categorized instead in [[Category:English terms with obsolete senses]], using {{lb|en|obsolete}} (template lb instead of tlb), which should typically be placed next to the individual sense.

Obsolete forms should be distinguished from archaic forms, which, although no longer in general use, are still occasionally used for special effect and are typically recognized by native speakers; and dated forms, which are merely unfashionable and anachronistic but still sometimes used, especially by older speakers.