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The Latin alphabet of the time still lacked the letters ⟨j⟩ and ⟨w⟩, and there was no ⟨v⟩ as distinct from ⟨u⟩; moreover native Old English spellings did not use ⟨k⟩, ⟨q⟩ or ⟨z⟩. The remaining 20 Latin letters were supplemented by four more: ⟨æ⟩ (æsc, modern ash) and ⟨ð⟩ (ðæt, now called eth or edh), which were modified Latin letters, and thorn ⟨þ⟩ and wynn ⟨ƿ⟩, which are borrowings from the futhorc. A few letter pairs were used as digraphs, representing a single sound. Also used was the Tironian note ⟨⁊⟩ (a character similar to the digit 7) for the conjunction and, and a thorn with a crossbar through the ascender for the pronoun þæt. Macrons over vowels were originally used not to mark long vowels (as in modern editions), but to indicate stress, or as abbreviations for a following m or n.

What is the term for the letter þ?
thorn