入

The core sense is the transition from outside to inside via the crossing of a threshold. This manifests in three primary domains:

• Physical/Spatial: Entering a place (e.g., city, house, forest).
• Institutional/Social: Joining a rank, court, or sect; denotes absorption into a system and a change in status.
• Abstract/Internal: Transitioning into states of being (e.g., dreams, death); the penetration of an idea or feeling into the heart (入心); or philosophical attainment/ontological shift (e.g., 入道).

Primarily a transitive verb; occasionally functions as a noun referring to an "entrance" or the "act of coming in." In early texts, it carries inherent directionality without requiring a preposition. When followed by a person, it may mean "approach" or "come to" rather than literal entry.

Contrast with 进: while both involve movement toward a destination, 入 emphasizes the crossing of the boundary (the threshold), whereas 进 emphasizes advancement or progress toward a goal.

In later administrative or economic contexts, the glyph evolved to denote income or revenue.

Note the visual similarity to 人 (person), particularly in early scripts.

Because 入 frequently functions as part of a binary with 出 (exit), translators should scan the passage for the latter to determine if the author is establishing a boundary or a cycle.