Judgments rendered by Anglo-American courts are often referred to as “opinions.” In this context “opinion” is “a court’s written statement explaining its decision in a given case, usually including the statement of facts, points of law, rationele and dicta” (Black’s Law Dictionary, 8th. ed.). I’ve recently seen several Spanish texts that used “opinión” to refer to the decision of a court that would have perhaps been better described as either its “sentencia” or “fallo.” Other related expressions worth noting include

• separate opinion (voto particular)
• dissenting opinion (voto particular disidente/discrepante)
• concurring opinion (voto particular concurrente)
• judge delivering the opinion of the Court (magistrado ponente)
• “It is the opinion of this Court…” (“Es el parecer de esta Sala/de este Tribunal…”)

In other respects, dictamen no vinculante is an “advisory opinion” and dictamen pericial is an “expert witness opinion,” while what is widely known in civil law countries as doctrina can be appropriately rendered as “academic opinion” (or also as “legal scholarship,” “scholarly writing” or perhaps “the writings of law professors and legal scholars”).