The term "g25gle" is a play on the word "Google" and was used to celebrate Googles 25th birthday. It was used in a special Doodle and some surprises in Search to mark the occasion. The hashtag #G25gle was also trending on social media. The term has no other meaning or definition outside of its use in relation to Googles 25th anniversary. It is important to note that "gaggle" is a different word with a different meaning, referring to a group of noisy or silly people.