IPA: /ˈbreɪkθruː/
KK: /ˈbreɪkˌθru/
A significant achievement that allows for further progress, especially in fields like science or technology.
The scientist made a breakthrough in cancer research that could save many lives.
Breakthrough → It is formed from "break" (from Old English "brecan", meaning to shatter or destroy) and "through" (from Old English "þurh", meaning by means of or across). The word "breakthrough" refers to a significant or sudden advance or discovery that occurs by overcoming obstacles.
Think of 'shattering' something ('break') and then moving 'across' or 'by means of' it ('through') — that's how a breakthrough represents a significant advance.