Revelation 1:1 and Signifying

"The revelation of Jesus Christ, which God gave him to show to his servants the things that must soon take place. He made it known by sending his angel to his servant John," (ESV)

"The Revelation of Jesus Christ, which God gave unto him, to shew unto his servants things which must shortly come to pass; and he sent and signified it by his angel unto his servant John:" (KJV)

"A revelation by Jesus Christ, which God gave him, to show his slaves the things that must shortly take place. And he sent his angel and presented it in signs through him to his slave John" (NWT 2013)

"The Revelation of Jesus Christ, which God gave to him, to point out unto his servants the things which must needs come to pass with speed,—and he shewed them by signs, sending through his messenger, unto his servant John;" (Rotherham EB)

See the NET footnote for Rev. 1:1.

Regarding Rev. 1:1: for σημαίνω, BDAG Greek-English Lexicon has

(1) to make known, report, communicate

(2) to intimate someth[ing] respecting the future, indicate, suggest, intimate

(3) to provide an explanation for someth[ing] that is enigmatic, mean, signify.

Rev. 1:1 is categorized under (1) in this lexicon.

Grant R. Osborne's Remarks Concerning Rev. 1:1b:

The process of revelation is further described with ἐσήμανεν (esēmanen, made it known), the third term in 1:1 (with “revelation” and “show”) with the connotation of “revealing” God’s message. This term has a special purpose, for it is the verb cognate of the Johannine term σημεῖον (sēmeion, sign) and yields the idea of “making known” by means of symbols. This is particularly apropos in light of the predominant symbolism of the book. It is questionable whether Christ (in keeping with the centrality of Christ in 1:1) or God is the subject of “made known” (if ἐσήμανεν parallels δεῖξαι above). While the latter is possible grammatically, Christ is the one who “shows” the revelation to the church and therefore the likely one who “signifies” it to John. The means by which these symbolic truths are to be communicated is “through his angel,” and, as stated above in the introduction, angelic mediation is one of the hallmarks of apocalyptic literature. Even a brief perusal of this book proves the extent to which angels feature in the action.

See Osborne, Revelation, Baker Books, 2002 (Ebook published in 2012).

These comments from G.K. Beale equally illuminate Rev. 1:1:

The roots of this verse are in Dan. 2:28-30, 45-47, where in the Greek translations of the OT the verb “revealed” appears five times, the verb “show” (“signify,” “communicate,” Greek sēmainō [only in OG]) twice and the phrase “what must come to pass” three times.