Only Phrases

Meaning
This phrase is used when something is on the threshold that is between success and failure and slight change can lead to either a win or a loss.

Origin
The first citation was in 1970 in The Lima News:
“On the ‘bubble’ is rookie Steve Krisiloff whose 162.448 m.p.h. was the slowest qualifying speed last weekend. With only six spots open, Krisiloff’s machine would be ousted if seven cars qualified at a faster speed this week end.”