An ink bottle is a short, squat vessel for holding a writer’s ink; it’s also called an “ink flask”, “ink horn”, or “ink well”, though the shape remains unchanged. It’s normally found as half of a penner and inkhorn, but we have at least one period example of its use as a separate charge: the arms of Abbot, d.1487 [DBA2 314].
There is also the “ink pot”, more ornate and less portable than a standard ink bottle; though a period artifact, its use as a charge seems unique to Society heraldry. See also bottle, flask.
The West Kingdom College of Scribes bears: Sable, an ink flask Or.
The College of Boethius bears as a badge: Or, on an open book azure, an ink pot Or.
Ingrid the Fair bears: Or, three inkwells gules, on a chief azure a drakkar without sail argent.