blastós

Blastós is the Greek root blastos meaning bud, sprout, or germ. In scientific usage, it denotes an early, formative state or a tissue with developmental potential. The term appears in many embryological and regenerative terms and is foundational to describing growth and formation processes.

In embryology, the blastula is the early stage formed after cleavage of the zygote, typically a hollow ball of cells surrounding a fluid-filled cavity called the blastocoel. The individual cells produced during cleavage are called blastomeres. In many animals, the outer layer of cells in early development is referred to as the blastoderm. Gastrulation transforms the blastula into a gastrula, with the opening called the blastopore through which the digestive tract begins to form.

Blastema refers to a mass of relatively undifferentiated cells capable of proliferation and differentiation to regenerate tissues or organs, a concept central to regenerative biology and observed in species such as salamanders and some fish. The term highlights the germinal character of the tissue involved in growth and repair.

In mammalian development, terms such as blastocyst and embryoblast reflect early germinal stages. A blastocyst is a hollow ball of cells with an inner cell mass that will form the embryo proper, while the embryoblast is the inner cell mass itself. The use of blast- in these terms underscores the inherited sense of germ or bud in developmental biology.

Overall, blastós functions as a productive etymological source in biology for stages and tissues that are formative, germinal, or regenerative.