I opine you should better google or search each point at an encyclopedia or music site, once you want to know so many things at once, maybe without having had a basis on the subject. Anyway let me try to help you a bit, if you still need it, once there is no answer yet. 1. Classical music is said to be a style of music composed as a cult kind of art by scholars or players who could be teachers, conductors, masters and so on. It is a generic word for a fine type of music that has special structure in its creation, with proper characteristics, rules or patterns, standard instruments, determined forms and techniques and so on, thus different of pop, folk or popular music, which do not require really much or good knowledge of how-to - right? In this sense, in the West (from East Europe to Americas [westwards] and a bit of Oceania, maybe just a little bit of Africa, who knows?), the term covers the period of time from about 1560 to 1840. However due to changes in styles of composing or performing, the specifical Classical Music is meant to the era of Franz Josef Haydn to Ludwig van Beethoven's main activity, thus from 1750 to 1820, as before the former there was a way of making scholars' music that later became known as Baroque Music, and after the latter other forms appeared, being the period known as Romantic Music. 2. Chamber Music, within Western Classic Music (later, spread out to include any musical grouping alike), means a special way of composition and players (it may include voices too) for a small group of performers. At any period of time it might have been appeared, even up to now. Instruments are generally the same, but there are other possibilities; the most are so-called strings (meaning bows - violin, viola, cello, [double-]bass), flute, clarinet, oboe, harpsichord, organ or piano, and sometimes one or two other soloists, such as a horn, a trumpet, an acoustic [unplugged] guitar or other. In real Classical Music, the main form (a genre of pieces) was named sonata, having real pattern to be followed in composition, either for a soloist only or for a duo, a trio, or other [very small] group of instruments (sonata was not made for human voice), also for a soloist with [small group] accompaniment. 3. Orchestral Music: Pieces composed for a larger group of instruments, including percussion (or not); normally in a Classical Orchestra there are four groups (or small ensembles of instruments having the same stuff in their making): winds or wooden [flute, oboe, clarinet, bassoon]; metals [horn, trumpet, trombone, tuba] - note that saxophones were created after the basic classical orchestras had been structured, so they still are taken as popular instruments, used in jazz, folk and other types of music -; percussions (these vary, but basically there are timpani, tambourine, triangle, cymbals, xylophone and others alike, bells or cow-bells, snare drums, bass drum and gong etc.; occasional soloist [harp, mandoline, guitar - or one of the standardised in traditional classical orchestra, depending on the type of composition]; bows [violins, violas, violoncellos, double-basses]. A symphony is a type of composition for a whole (as per classical pattern) orchestra; a concerto is other kind of composition on which the orchestra plays together and/or accompanying a soloist or a pretty small group of soloists (the latter happened more usually in Baroque era). A pure solo concerto would be like a sonata, as above mentioned, having no meaning properly; but sonata for Baroque musicians was not like for Classical ones, so a solo concerto is possible (???). 4. String Quartet is what Classical musicians and scholars named a composition and/or performance for bows (normally, two violins, one viola and one cello), but there were some variations of this standard, such as a quartet for clarinet and strings (thus one violin was absent - no score was written to it, as commonly). 5. Movements are parts (like divisions, not equal) of a composition (since before the Baroque time they made diversified parts for a musical larger piece), many times being contrasting in speed; thus there are for instance Largo / Adagio / Andante / Allegretto / Allegro / Vivace, and these and others can be added an adjective meaning the way that part should be performed (calm, or rigid, or funny - all nouns and adjectives in scores are basically written in Italian; do you guess why???). There does not exist a "sonata Allegro", but an "Allegro" of a "sonata" - ok? 6. Theme & Variations / Minuet & Trio / Rondo = not movements properly, but forms of composition, meaning rather that they are like dances or not (Minuet was so common as a popular dance [just arranged in cult structure] even before the Baroque era and after some Romanticists), also how they are structured and must be performed; these terms are for speed too, but not in an exact time. "Theme & Variations" is common as an exercise of composition (using a musical idea and creating some "logical" or not "diversified similar" ways of it), but some authors made some of them really worthy to appear as a part of a concert (a performance); "Rondo" is a piece with an idea that returns times by times as long as music flows, normally used as a final movement for a symphony or mostly for a concerto. NOTE: I am no musician at all, properly!!!
