On hearing the various parts of the suit of armour mentioned, and being fascinated by the development of words, I soon began looking at the etymologies of some of the many terms used for parts of a suit of armour, and beginning with .....
Armour, and obviously the parts going to make it, as we most commonly perceive it was brought to England by the Normans. The earliest surviving use in English dates from 1297, coming from the Old French amure and derived from the Latin armatura meaning 'arms and/or equipment' and from the root armare 'arms or gear'. Note it is only in recent times we have used 'suit of armour', for most of its life it has simply been 'armour'.
Armet is a bowl-shaped helmet covering the entire head and does not have a visor, but folding panels at the cheeks. Clearly the term shares its etymology with the word 'armour'.
Aventail is a piece of chainmail attached to the skull of the helmet covering the neck, throat and shoulders. It comes from the Old French esventail meaning 'air hole'.
Baldric, which is undoubtedly going to prove the most popular in this list, is a belt worn over the shoulder and thus little surprise to find it is from the Old French baldre meaning 'shoulder belt' and a variation on the original Latin balteus meaning 'belt'.
Brassard, that part protecting the arm, comes from Old French bras ard meaning literally 'arm hard'.
Breastplate is clearly a combination of two monosyllablic words. Thus taking each in turn we find the earliest root of 'breast' to be the Proto-Indo-European bhreus meaning 'to swell, sprout'. Oddly 'plate' is a much more recent word - as a table utensil unknown until the 15th century - and originally used to mean anything flat, it comes from the Greek platys 'flat, broad'.
Burgonet is another bowl-shaped helmet but with the distinctive crest. Despite this only being from the 16th century the origins are not clear, however this could be a feminine version of bourgignot and thus 'the Burgundian'.
Coif is the balaclava-like hood of mail, this from Old French coife and other contemporary terms sharing a meaning of 'cap'.
Cuirass is a breastplate, although also used to describe both breast and back plates together. It comes from Latin coriacea vestis 'garment of leather' and earlier from corium 'leather' or 'hide'.
Helm and helmet have idential origins, both ultimately from Proto-Indo-European kel meaning 'to cover, hide'.
Cervelliere is derived from Old French cervel meaning 'brain, head' and is the steel cap worn under the helm.
Bassinet is more headwear and easily seen as coming from the same source as 'basin' and ultimately from bacca 'water vessel'.
Culet is the skirt-like strips of metal covering the buttocks and derived from Old French cul 'bottom' and ultimately from Latin culus 'arse'.
Gauntlet, most often used today as part of a phrase meaning a challenge, is from Proto-Germanic wantuz 'glove'.
Gorget is the name given to the steel collar attached to the top of the breast and back plates. It is derived from Latin collare 'necklace band', earlier kwol-o 'neck' and itself from the root kwel 'move about, turn'.
Hauberk, also recorded as Haubergeon, is a coat of mail which lengthened over the centuries until it came to the knee. Possibly the name tells us the earliest forms had no sleeves, thus really a cape of mail, as the name shares an origin with the previous entry where Proto-Germanic hwals and Proto-Indo-European kwolso referred to the 'neck'.
Tuille are the bands hanging from the breastplate to protect the top of the legs. Here the origins are Old French teuille and Latin tegula meaning 'tile'.
Vambrace is the forearm guard and means just that - avant 'before' and bras 'an arm'.
Visor is from Old French visere and from vis or 'face'. Both are derived from Latin videre 'to see'.