Definition, synonyms and related words
plural of balloon
"The children filled their balloons with helium before letting them float away into the sky."
Third-person singular simple present indicative form of balloon; Enlarges, gets bigger
"The hot air balloon rises as it enlarges into the sky."
In plain English: To balloon means to grow very large and round quickly, usually because of air rushing inside you.
"The pressure inside the tank began to balloon before anyone could shut off the valve."