A widow's mite is a small bronze coin. We do not know for certain which coin, but the most likely is a Judaean Prutot of Alexander Jannaeus (103 to 76 BC).
you can see examples of Widow's Mites here and below:
The obverse legend is "...TRAIANO AVG...AC PM TRP COS V PP"
Looking at Wildwinds, four bronzes are shown which have that legend (there may be more which aren't represented in Wildwinds):
Trajan Æ Sestertius. IMP CAES NERVAE TRAINO AVG GER DAC PM TRP COS V PP, laureate bust right / S.P.Q.R. OPTIMO PRINCIPI, Annona standing left, holding grain ears and cornucopiae; modius with grain ears and prow at her feet; SC. Cohen 469.
Trajan 98-117 AD. AE Sestertius, 27.21 gr. Struck 103-111 AD. IMP CAES NERVAE TRAIANO AVG GER DAC PM TRP COS V PP, laureate head right, slight drapery on left shoulder / SPQR OPTIMO PRINCIPI, S-C Fortuna standing left, holding rudder before prow, and cornucopiae. RIC II 500; BMCRE 797; Cohen 477; Sear (1988) 1008.
Trajan AE Dupondius. IMP CAES NERVAE TRAIANO AVG GER DAC PM TRP COS V PP, radiate bust right / SPQR OPTIMO PRINCIPI S-C, Fortuna standing left with rudder on prow and cornucopiae. Cohen 497.
Trajan AE Sestertius. IMP CAES NERVAE TRAIANO AVG GER DAC PM TRP COS V PP, laureate bust right / SPQR OPTIMO PRINCIPI S-C, View of the Circus Maximus, showing a colonnaded front (the Duodecim Portae), with arched gateways surmounted by quadrigae; temple of Sol along back wall; within, from left to right: meta, equestrian statue of Trajan, obelisk of Augustus, shrine of Cybele, and a second meta. RIC II 571; Woytek 175b; Cohen 545.