Katakana (カタカナ) is one of the two sets of syllable writing used in Japanese. Katakana is most often used for foreign terms, foreign names.
Today's Japanese is written in a mixture of three writing systems, two of them syllable sets, hiragana (the squiggly letters), katakana (the edgy ones) and kanji (the small pictures with the many strokes).
When looking at a Japanese word, the kanji can give a hint about the original meaning or the concepts involved in the expression. Some go terms are written in katakana.
Examples of words in katakana: ピアノ バナナ テンイス ゴルフ コーヒー ビール