Hōrensō means spinach. It is also made of the first syllables of three workplace words: hōkoku (report), renraku (inform) and sōdan (consult).
Around 1982, Yamazaki Tomiji, president of Yamatane Securities, started a “spinach campaign” in his company. His book on it, Hōrensō ga kaisha o tsuyoku suru (Spinach Makes a Company Strong), appeared in 1986. One account says the idea came from his father.