border
noun
the part or edge of a surface or area that forms its outer boundary.
Used to describe an action that was ongoing continuously in the past up until another past event interrupted it.
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
Elise had been gay and talkative with a forced vivacity; and Lady Durwent had been bordering on hysteria.
From The Parts Men Play by Arthur Beverley Baxter