Skip to Main Content

We have a new app!

Take the Access library with you wherever you go—easy access to books, videos, images, podcasts, personalized features, and more.

Download the Access App here: iOS and Android. Learn more here!


(for′māt) A salt of formic acid.


1. A particular structure. 2. An arrangement. 3. The giving of form or shape to, or the development of, a structure.

capsule f. The development of scar tissue around a structure; encapsulation.

endochondral bone f. One of the two types of bone formation in skeletal development. Each long bone is formed as a cartilage model before bone is laid down, replacing the cartilage.

hippocampal f. Limbic structures lying along the medial temporal lobe. They include the hippocampus proper, the dentate gyrus, and the subiculum.

reticular f. A diffuse complex of nuclei, axons, and dendrites extending rostrocaudally through the entire core of the brainstem. Some of the reticular nuclei are sufficiently distinct to have names and functional descriptions. In the midbrain, the reticular formation includes the pedunculopontine and cuneiform nuclei. In the rostral hindbrain, the formation includes the caudal and oral pontine reticular nuclei and the reticulotegmental and superior central nuclei. In the caudal hindbrain, it includes the lateral, gigantocellular, and paramedian reticular nuclei. The inputs to the reticular formation come from the sensory, cerebellar, cortical, striatal, and limbic systems; the outputs of the formation are carried by reticular axons throughout the nervous system from the forebrain to the caudal spinal cord. Signals from the midbrain and rostral hindbrain reticular formation control the level of the brain’s alertness; signals from the hindbrain reticular formation help control body posture; and signals from other parts of the reticular formation control homeostatic processes, e.g., the rate and rhythm of respiration.

root f. The development of tooth roots by the Hertwig root sheath and the epithelial diaphragm. It involves the formation of root dentin with a covering of cementum essential for the attachment of the tooth to the surrounding bony tissues. Root formation continues for months or years after the tooth has erupted into the mouth.

formative assessment

In educational theory, a measure of a student’s ongoing learning, achievements, retention, and knowledge use, followed by feedback and tailoring of education to correct any identified deficiencies.

form constancy

The ability to identify an object even when it is rotated, reversed, or displaced spatially. In reading, for example, it is the ability to identify the similarities and differences between the letters “p” and “q” or the letters “b” and “d.”

forme fruste

(form froost) pl. formes frustes [Fr., defaced] An aborted or incomplete form of disease arrested before running its course; an atypical and indefinite manifestation of an illness.


(for′mĭk) [L. formica, ant] Pert. to ants or to formic acid.

formic aldehyde


Pop-up div Successfully Displayed

This div only appears when the trigger link is hovered over. Otherwise it is hidden from view.