Katakana and hiragana are both syllabaries. In English we use the letters of the alphabet. In most words each letter stands for a bit of sound (a phoneme). In a syllabary each symbol stands for a syllable. For example: in English we write “Wagamama”: each of the eight letters standing for a sound: “W-a-g-a-m-a-m-a”. But if the word “Wagamama” is divided into syllables there are four syllables (blocks of sound): Wa-ga-ma-ma. In Katakana it is written with four symbols: ワガママ.