
1) English-language opera 2) Identifying marks 3) Opera based on novel 4) Scandinavian girl name
Found on
https://www.crosswordclues.com/clue/signa
[opera] Signa is an opera originally conceived in four acts with music by the British composer Frederic H. Cowen with a libretto by Gilbert Arthur à Beckett, with revisions by H.A. Rudall and Frederic Edward Weatherly after Ouida, with an Italian translation by G.A. Mazzucato, first performed in a reduced three act version at the Teatro Da...
Found on
http://en.wikipedia.org/wiki/Signa_(opera)

(sig´nә) Latin word meaning write or make a mark; abbreviated S. or sig.. It is used in writing prescriptions and is followed by the signature.
Found on
http://www.encyclo.co.uk/local/21001

Those species of indicia which come more immediately under the cognizance of the senses, such as stains of blood on the person of one accused of murder, indications of terror at being charged with the offence, and the like. Signa, although not to be rejected as instruments of evidence, cannot always be relied upon as conclusive evidence, for they.....
Found on
http://www.lectlaw.com/def2/s155.htm

standards The standards of all Roman military units were held to be sacred, thus they were stored in the most holy of places within the fort's defences, the sacellum, or military shrine in the rear range of the principia. The signa or regimental standards were housed alongside the vexilla or flags of the individual centuries or decuries of the garr...
Found on
https://www.encyclo.co.uk/local/20768
No exact match found.