A stream is a small river or current of water, drawn in a naturalistic style. In medieval armory, streams are usually found in combination with other charges, such as a bridge; but they are also found as charges in their own right, as in the arms of da Cabrin, mid-15th C. [Triv 109]. The period examples of streams tend to show them in base and throughout, but nonetheless that doesn’t seem to be a default; it is best to be explicit. The illustration shows a stream fesswise throughout in base.
There are also examples of ordinaries wavy (e.g., the bend wavy in the arms of von Büren, 1605 [Siebmacher 167]) which have been diapered to represent running streams. The diapering in these cases is considered artistic, worth no difference, but the intent is clear: indeed, the canting arms of Sardinha, c.1540 [Nobreza xxxv°], even charges a bend wavy, diapered as a stream, with a strewing of sardines, to make clear the watery nature of the charge.
A highly stylized depiction of a stream is found in Japanese Mon, as borne by Okamoto [Hawley 26]; it might be blazoned, awkwardly, as “barrulets bevilled arrondi”. The difficulty of accurately blazoning it in European heraldic terms makes the Japanese stream unregisterable in Society armory. For related charges, see base (ford), wave.
Ishiyama Namban Tadashi bears: Argent, in chief a barrulet gemel bevilled arrondi and issuant from base a wave reversed sable.
Grímr Víthfari bears: Or, atop a bridge of three arches throughout a tower, the streams transfluent gules.