The abaxial surface of a leaf is the underside or side facing away from the stem.    From Wordnet, Princeton University. 

Adjective : the abaxial surface of a leaf.    From Dictionary.com. 

The coronary band Pulvinus coronae lies in the coronary groove immediately distal to the periople corium, proximal to the parietal surface of the distal phalanx, and abaxial of the ungular cartilages of the foot.    From Wordnik.com.  [Ed Ltd | SciFi, Fantasy & Horror Collectibles] Reference

(I) The lgo-1 abaxial leaf epidermis lacks giant cells.    From Wordnik.com.  [PLoS Biology: New Articles] Reference

The largest group of cells in the outer (abaxial) sepal epidermis of.    From Wordnik.com.  [PLoS Biology: New Articles] Reference

Typically, the stomata are more numerous over the abaxial (lower) epidermis than the (adaxial) upper epidermis.    From Wordnik.com.  [Wikibooks - Recent changes [en]] Reference

The number of cells in the lgo-1 abaxial epidermis is increased as expected because multiple small cells replace giant cells.    From Wordnik.com.  [PLoS Biology: New Articles] Reference

Conversely, pATML1:: KRP1 sepals have fewer cells in the abaxial epidermis because the additional cells entering the giant cell pathway have no progeny.    From Wordnik.com.  [PLoS Biology: New Articles] Reference

We use live imaging to determine the timing and position of each cell division in the outer (abaxial) sepal epidermis and track the lineages of these cells throughout early sepal development.    From Wordnik.com.  [PLoS Biology: New Articles] Reference

They form, in the ectodermal layer, isolated basi-epithelial spots concentrated in the more distal part of the bulb and in the tentacle base, and also more concentrated on the abaxial side of the bulb (figure 3B).    From Wordnik.com.  [PLoS ONE Alerts: New Articles] Reference

Most leaves show dorsoventral anatomy: the upper (adaxial) and lower (abaxial) surfaces have somewhat different construction and may serve different functions. transparent (epidermal cells lack chloroplasts) and coated on the outer side with a waxy cuticle that prevents water loss.    From Wordnik.com.  [Wikibooks - Recent changes [en]] Reference

Petiole 2-6 mm, puberulent and ± setose; leaf blade papery, oblong to oblong - lanceolate, 5-11 × 1. 5-3.5 cm; base cuneate; margin ciliate; apex obtuse and mucronate; abaxial surface densely gray-white-pubescent, yellow-brown setose along midrib; adaxial surface sparsely to densely puberulent when young.    From Wordnik.com.  [Find Me A Cure] Reference

From abaxial to zygospore.    From Wordnik.com.  [111715167698185767 « ResourceShelf] Reference

1,600 cells in the front (abaxial) epidermis and about 2,800 in the back (adaxial) epidermis.    From Wordnik.com.  [PLoS Biology: New Articles] Reference