Squillion is not a standard English word, however, synonyms for it include the word "gazillion", which is an exaggerated or informal way of referring to an extremely large, unspecified, or imaginary number. There is also "jillion", a similar word that is likewise an informal way of referring to an imaginary, indeterminate, or vast number. "Zillion" is yet another informal and playful way of indicating an immeasurably large or indefinite amount. Lastly, there is "googol", which is an actual mathematical term that refers to the number one followed by one-hundred zeros. Overall, all these words represent an immense or unimaginable amount that is impossible to count.