Arabic Shadda Isolated Form

It marks a consonant as doubled. An isolated shadda sample such as ﹼ has no letter to modify; it shows the mark by itself. In دَرَّسَ, shadda marks the doubled middle consonant; in دَرَسَ, that consonant is single.

Arabic diacritics—marks added to letters to guide reading—are documented in an inscription from 644–645, but that does not date the exact modern shadda shape. In a Qurʾān codex from the late eighth or ninth century, a red semicircle has been identified as shadda in one place; the reading is contested.

Notation varied by setting. Red dots were standard in Qurʾān manuscripts from the early eighth until the late tenth or eleventh century; a letter-shaped system attributed to the scholar al-Khalīl spread through non-Qurʾānic books. In literary Syriac, combining shadda U+0651 can appear over Syriac waw ܘ in the address “O!”; that is a reuse of the combining mark, not this isolated form.

Which shadda should you type?

For ordinary Arabic, use the combining shadda U+0651 after its letter. Unicode keeps FE7C as a legacy form for older text systems. Its mapping is a space followed by U+0651, so the mark stands alone instead of attaching to a base letter.

Type U+0651 after the letter being marked and let Arabic shaping place it. Reserve ﹼ for an exact legacy record, compatibility test, or character specimen; it is not the form for ordinary prose.