What does "abaxial" mean?

1. (facing away from the axis) describing the side of a plant part, like the bottom of a leaf, that faces away from the stem. 2. (displaced from the axis) not located on the main central line, such as a seed embryo that is off-center.

How do you use "abaxial"?

Usually placed before the noun it modifies. Used as a non-gradable adjective.

abaxial

abax·i·al

1 facing away from the axis (adj.)
C2 Proficiency Technical Science

describing the side of a plant part, like the bottom of a leaf, that faces away from the stem.

situated on the side facing away from the axis or central line of an organ, such as the lower surface of a foliage leaf.

Example

The abaxial surface of the leaf is often lighter in color than the top.

Example

Microscopic examination revealed that the stomata were primarily concentrated on the abaxial epidermis to minimize water loss through transpiration.

Usage

Usually placed before the noun it modifies.

Teacher's tip

This is a highly specialized term; learners should use 'underside' or 'bottom' in general contexts unless writing a formal biology report.
- dorsal
- underside
- adaxial
2 displaced from the axis (adj.)
C2 Proficiency Technical Science

not located on the main central line, such as a seed embryo that is off-center.

positioned away from or outside of the central axis, particularly regarding the placement of an embryo within a seed.

Example

The scientist noted that the seed had an abaxial embryo.

Example

The classification of the genus was partially determined by the abaxial position of the embryo relative to the endosperm.

Usage

Used as a non-gradable adjective.

Teacher's tip

This sense is even more restricted than the first and is almost exclusively found in botanical descriptions of seeds.
- off center
- eccentric
- axial

Origin

From ab- (“away from”) + axial (“axis”).