blastocyst

noun

blas·​to·​cyst ˈbla-stə-ˌsist 

: the modified blastula of a placental mammal having an outer layer composed of the trophoblast

Examples of blastocyst in a Sentence

Recent Examples on the Web

For example, synthetic blastoids develop a blastocoel cavity and the three main cell types (epiblast, trophectoderm, and primitive endoderm) within one week, just like natural blastocysts. —Srishti Gupta, Interesting Engineering, 28 Mar. 2026

When sperms managed to reach the eggs, the ensuing early-stage embryos, called blastocysts, initially appeared stronger than their counterparts conceived in gravity. —Tereza Pultarova, Space.com, 27 Mar. 2026

With this defining feature, the zygote becomes a blastocyst, ready to embed itself in the lining of the uterus. —Clare Watson, Quanta Magazine, 27 Feb. 2026

By this time the embryo has reached the hollow ball stage, called a blastocyst. —Literary Hub, 20 Feb. 2026

Word History

Etymology

blasto- + -cyst

First Known Use

1876, in the meaning defined above

Rhymes for blastocyst

• bolshevist
• coexist
• egoist
• hedonist
• jihadist
• nativist
• oculist
• reminisced
• assist
• blacklist
• booklist
• checklist

Medical Definition

blastocyst

noun

blas·​to·​cyst ˈblas-tə-ˌsist 

: the modified blastula of a placental mammal