Financial ratios are relationships determined from a company's financial information and used for comparison purposes. Examples include such often referred to measures as return on investment (ROI), return on assets (ROA), and debt-to-equity, to name just three.
Tremolo harmonica. Tremolo harmonicas are a type of harmonica, distinct by having two reeds per note. In a tremolo harmonica the two reeds are tuned slightly off a reference pitch, one slightly sharp and the other slightly flat. This gives a unique wavering or warbling sound created by the two reeds being not exactly in tune with each other and difference in their subsequent waveforms acting against one another.
It went to the West (probably with Marco Polo) and was eventually incorporated in new free-reed instruments (reed organs, harmonicas, accordions, concertinas etc) in the 19th century. So the modern harmonica is essentially a Chinese/Western fusion instrument.