Keyboard Cavalcade

There have reportedly been proto-versions of the organ (essentially, with one or more ranks of wind-blown pipes controlled from a keyboard) since Roman times (i.e. somewhat over 2,000 years ago); keyboard instruments with plucked or hammered strings date back at most about a third as far as that, to the Middle Ages

The organ with the most keyboards was built by Midmer-Losh at the Boardwalk Hall in Atlantic City (see here): it has no fewer than seven manuals (so even a player 'thumbing-down' twice-over could still only be using barely half of them at once), plus the pedalier. A common-or-garden church or theatre instrument would have two or three manuals; a cathedral might have four or possibly five; there are plenty of chamber and continuo organs with only one manual and no pedals at all

It is known that Bach tried some early Silbermann pianos, made various positive technical suggestions and enjoyed playing such instruments in the mid-1730s. The first heyday of the Piano Sonata and Concerto were by then only a generation or so into the future; Mozart was dead by the end of that century, for instance

The upper three instruments each have buttons (though a piano-accordion would have a short-compass piano-style keyboard at the treble end, and chord buttons at the bass); the harmonium (more or less the same thing as a Reed Organ) only has a piano-style 'interface'

The 'jacks' are/were the vertical wooden components which leap up when a key is pressed, and whose motion leads to the relevant string being plucked by a quill ~ hence that the timbre of such an instrument sounds somewhat similar to a plucked guitar or mandolin. Sometimes the vigorous player would put too much energy into it, and the jack would leap up and then fall back out of its proper place so that it would be stuck and not respond the next time that key were played

Chopin was widely referred to by this title: he was perhaps one of the best examples in musical history of someone who came along at the right time in the development of the technology. The pianos of his day were less powerful than ours now, but could still express both quiet soulfulness (as in his Nocturnes) and a roaring or playful energy; this range of emotions was emerging from the private salon into the concert hall, in a period when Europe had been convulsed by the Napoleonic Wars and the early stages of the Industrial Revolution

This is the true purpose of the 'sostenuto' pedal (as distinct from the common-or-garden Damper Pedal, always the rightmost of the cluster). You would be unlikely to find a third, middle pedal having a mute function on a concert grand piano, though this is far more likely on a modest upright (e.g. for quieter practice in a home or flat)

The number on a stop control is usually a foot-length. If you consider it, many instruments that play upwards from middle C are indeed about 2ft long (such as the violin, clarinet or indeed the trumpet, where the whole instrument lies within arm's-length from the player's head or neck); lower-playing instruments are larger (e.g. the cello or trombone). This correlation between physical length and sounding pitch also explains the classic shape of instruments with many sounding parts such as the harp, piano and ranks of organ pipes, each with the deepest sounding components at one end and the shrillest at the other.
Some organ stops have other equivalent markings on them such as fractions or Roman numerals ... a tad too technical to go into here!

The Spoon is part of the action of a grand piano (so named because, at the back of the key lever, it raises ~ with a spoon-like, encouraging upward motion ~ the part of the mechanism that disengages the damper from the string while the hammer is on its way to hit it). All the other parts named here are components within the action of a mechanical pipe organ

The glockenspiel and xylophone, though laid out with their sounding parts to mimic the shape of a keyboard, are struck directly with sticks and therefore have no keyboard 'interface' as such; the Ondes Martenot does have a keyboard, but that's only part of its story!