墨

1. Origins, structure, and basic meaning

• Structure: 墨 is read as すみ and is a noun for an ink stick ground on an inkstone or the black ink produced from it.
• Basic usage: Grinding ink on an inkstone appears in 硯で墨をする, while a drop of ink falling from a brush tip appears in 筆の先から墨が一滴落ちる.

2. Common pitfalls and similar expressions

• Solid ink and liquid ink
  • Depending on context, 墨 can refer both to the ink stick being ground and to the liquid ink used with a brush.