bamboo flute with seven holes
篪 refers specifically to a type of bamboo flute with seven holes, an ancient wind instrument.
篪 combines 竹 (bamboo) with 虒, which likely contributes the sound. The character denotes a specific bamboo flute.
The top 竹 is bamboo, and the bottom 虒 looks like a tiger 虍 with legs 儿, perhaps suggesting the flute's shape or sound. Imagine a bamboo flute carved with a tiger motif, its seven holes producing a growling melody.
For チ, imagine the flute playing a cheerful 'chee' sound: chee -> チ, as the bamboo flute trills a bright note.