uncia (unit)

{{Short description|Ancient Roman unit of length}}

{{Infobox unit

| bgcolor =

| name = Roman inch

| image =

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| standard = Roman

| quantity = length

| symbol = 𐆑

| symbol2 =

| namedafter =

| extralabel =

| extradata =

| units1 = SI base units

| inunits1 = 24.6 mm

| units2 = U.S. customary

| inunits2 = 0.97 in

| units6 =

| inunits6 =

| units_imp1 =

| inunits_imp1 =

| units_imp6 =

| inunits_imp6 =

| units_us1 =

| inunits_us1 =

| units_us6 =

| inunits_us6 =

}}

The {{lang|la|uncia}} (plural: {{lang|la|unciae}}, lit. "a twelfth") was a Roman unit of length, weight, and volume. It survived as the Byzantine liquid ounce ({{langx|grc|οὐγγία}}, oungía) and the origin of the English inch, ounce, and fluid ounce.

The Roman inch was equal to {{frac|12}} of a Roman foot ({{lang|la|pes}}), which was standardized under Agrippa to about 0.97 inches or 24.6 millimeters.{{cn|date=April 2021}}

The Roman ounce was {{frac|12}} of a Roman pound.{{Citation |title=Oxford English Dictionary, 1st ed. |contribution=ounce, n.¹ |date=1911 |publisher=Oxford University Press |location=Oxford}}.