Septum

septa) is a wall, dividing a cavity or structure into smaller ones.

Histological septa are seen throughout most tissues of the body, particularly where they are needed to stiffen soft cellular tissue, and they also provide planes of ingress for small blood vessels.

[citation needed] Because the dense collagen fibres of a septum usually extend out into the softer adjacent tissues, microscopic fibrous septa are less clearly defined than the macroscopic types of septa listed above.

[18] Annelids have septa that divide their coelom into segmented chambers.

[19] Many shelled organisms have septa subdividing their shell chamber, including rhizopods, cephalopods and gastropods, the latter seemingly serving as a defence against shell-boring predators.

The lingual septum can be seen running vertically through the center of the tongue.
Alveolar septa (AS)
Septins in Saccharomyces cerevisiae
Septate hyphae of the fungus Alternaria , showing the septa between individual cells
A tomato has septa that divide the fruit into chambers ( locules ) that contain the seeds.