1.  aegis(n = noun.act) auspices, protection - kindly endorsement and guidance; "the tournament was held under the auspices of the city council"
is a kind of endorsement, indorsement

2.  aegis(n = noun.artifact) breastplate, egis - armor plate that protects the chest; the front part of a cuirass;
is a kind of armor plate, armor plating, armour plate, plate armor, plate armour
is a part of body armor, body armour, cataphract, coat of mail, suit of armor, suit of armour
has particulars: plastron

aegis, n. a protection; an impregnable defence.

Idiom:
under the aegis of under the auspices of.

Etymology:
L f. Gk aigis mythical shield of Zeus or Athene

N  defense, protection, guard, ward, shielding, propugnation, preservation, guardianship, area defense, site defense, self-defense, self-preservation, resistance, safeguard, balistraria, bunker, screen, camouflage, fortification, munition, muniment, trench, foxhole, bulwark, fosse, moat, ditch, entrenchment, intrenchment, kila, dike, dyke, parapet, sunk fence, embankment, mound, mole, bank, sandbag, revetment, earth work, field- work, fence, wall dead wall, contravallation, paling, palisade, haha, stockade, stoccado, laager, sangar, barrier, barricade, boom, portcullis, chevaux de frise, abatis, abattis, abbatis, vallum, circumvallation, battlement, rampart, scarp, escarp, counter-scarp, glacis, casemate, vallation, vanfos, buttress, abutment, shore, breastwork, banquette, curtain, mantlet, bastion, redan, ravelin, vauntmure, advance work, horn work, outwork, barbacan, barbican, redoubt, fort-elage, fort-alice, lines, loophole, machicolation, sally port, hold, stronghold, fastness, asylum, keep, donjon, dungeon, fortress, citadel, capitol, castle, tower of strength, tower of strength, fort, barracoon, pah, sconce, martello tower, peelhouse, blockhouse, rath, wooden walls, bulletproof vest, armored vest, buffer, corner stone, fender, apron, mask, gauntlet, thimble, carapace, armor, shield, buckler, aegis, breastplate, backplate, cowcatcher, face guard, scutum, cuirass, habergeon, mail, coat of mail, brigandine, hauberk, lorication, helmet, helm, bassinet, salade, heaume, morion, murrion, armet, cabaset, vizor, casquetel, siege cap, headpiece, casque, pickelhaube, vambrace, shako, bearskin, panoply, truncheon, garrison, picket, piquet, defender, protector, guardian, bodyguard, champion, knight-errant, Paladin, propugner, bulletproof window, hardened site, defending, defensive, mural, armed, armed at all points, armed cap-a-pie, armed to the teeth, panoplied, iron-plated, ironclad, loopholed, castellated, machicolated, casemated, defended, proof against, armored, ballproof, bulletproof, hardened, defensively, on the defense, on the defensive, in defense, at bay, pro aris et focis, Int, no surrender!, defense not defiance, Dieu defend le droit, fidei defensor, defender of the faith.