Hangul syllable Gaegs

It is one Korean syllable written as a block.

It joins the initial consonant ㄱ, vowel ㅐ, and final consonant cluster ㄳ. The block gives a syllable, not a complete word; its meaning depends on the Korean spelling around it.

Where did Hangul syllable blocks come from?

Hangul groups sound letters into syllable blocks.

Hangul's development was completed in 1443. The Hunminjeongeum manuscript, a text introducing and explaining the writing system, was published in 1446. It describes forming each syllable from beginning, middle, and final sound parts, then arranging them as one written unit.

갟 is one combination made by that system, not a separately devised sign. Modern Korean syllables have precomposed block forms; some obsolete or Old Korean syllables can use conjoining jamo, the separate letter forms that join into a block. A Hangul block can resemble a Chinese character, but its parts are Hangul sound letters, not a Chinese ideograph broken apart.

How do I type or display 갟?

Use a Korean IME and enter the parts in order.

On a standard two-set Korean keyboard, enter ㄱ, then ㅐ, then ㄱ + ㅅ for the final cluster ㄳ; the IME combines them as 갟.

Hangul font rendering can shift the parts' placement, shape, and size without changing the character. A decomposed sequence also needs shaping support to display as one block.