Just like in English, where "good" becomes "better" and "best", some common Italian adjectives have irregular comparative and superlative forms. The adjectives grande (big) and piccolo (small) are the most frequent examples.
Maggiore and Minore
Instead of più grande (bigger), you will often see maggiore (greater, major). Instead of più piccolo (smaller), you will see minore (lesser, minor). Because they end in -e, they use the same form for masculine and feminine nouns, and change to -i in the plural.
When talking about family members, maggiore also means "older" and minore means "younger":
Massimo and Minimo
To express the absolute highest or lowest degree of something, use the absolute superlatives massimo (maximum, greatest) and minimo (minimum, least, lowest). Unlike maggiore and minore, these end in -o and change their endings to match the noun in both gender and number (-o, -a, -i, -e).
You can mix and match these forms to precisely describe extreme sizes, amounts, or severity: