[1] Not the celebrated "triumvir" Marcus Licinius Crassus Dives, 115-53 BCE, but his grandson of the same name (consul in 30 BCE). This identification is guaranteed because the episode in question here is on record: see further, next note.
[2] The Daldi (Daldes?) are unknown. There was a city called Daldis in Lydia (in ancient Asia Minor: see alpha 4025 and delta 30), but it would have long been under Greek and then Roman domination in Crassus' day. Thus *da/ldwn here appears to be textually corrupt. In the 1544 Basel edition of the Suda *ga/llon - "a Gallic king" - was suggested (and the Roman's name became *ko/ssos, i.e. Cossus). However, no such resort is needed because this episode is on record elsewhere, notably in Cassius Dio 51.24.4 (see in brief R. Syme, The Roman Revolution (Oxford 1939) 308-9), which C. Theodoridis in his Photius edition (vol.II p.LXXXIX) very plausibly identifies as the Suda's source. The victim was a king of the Thracian Bastarnae, called Deldo; his conqueror Crassus -- see the preceding note -- claimed the spolia opima but antagonized Octavian in doing so, and eventually (pace the present entry) had to settle for "the bare distinction of a triumph" (Syme).
[3] If a Roman commander with imperium killed an enemy king in hand-to-hand combat, he was allowed the rare honor of dedicating the spolia opima to Jupiter Feretrius. Cf. Livy 1.10; Plutarch, Romulus 16. The Latin adjective means "rich" or "plump." See further OCD4 s.v. (p.1394).