Perhaps「sun above horizon」as the DAWN, yet the Sun generally remains above the horizon all of most days until sunset, and not only at dawn…. Moreover, 'dawn' literally refers to the moment when a fraction of the Sun first appears each morning, as sunlight rays on the verge of dawn crack over the edge and curvature of the Earth, but not after the circle of the Sun fully appears above the horizon a few minutes later. In that sense, ON THE VERGE, or ON THE EDGE is clearly related to the imminent moment of being struck in open eyes or the face by an ejaculating burst of flashing bright sunlight, the first rays at the crack of DAWN (other cracks excepted for the moment).
　Also used as a simplification of an older glyph (詹) that includes elements of「looking upward dangerously, head and neck erect and arrayed while copulating in oral intercourse」with meanings of ON THE VERGE, ON THE EDGE, BRAGGADOCIOUS, TALKING TOO MUCH, FEMALE ROLE, EXCELLENT, GALL, CHUTZPAH, LORD, MASTER, HUSBAND, and CLIENT OF A BROTHEL (is that obvious enough? see 晁). External sources generally disregard these original meanings by only providing the definition as DAWNING, the DAWN, also as a type of enlightenment that may have occurred while visiting the service providers at any time of the day or night. This glyph perhaps is an example of the interchangeability of「sun」with the「tonguing mouth, say, oral intercourse」element that was apparent in the original glyph. Ignoring all the source meanings while thinking of this element only as「the dawn」generally renders the glyphs it has been used in as incomprehensible.
　In Japan, meaning「new year's day」perhaps due to the meaning of ON THE VERGE (both the end of one year and the start of another) and likely not a literal reference only to dawn, since the dawn has happened most every day of every year, so far. Of course, DAWN and DAWNING also refers to being「on the verge or edge」of daytime, and the dawning of a new year. But perhaps, dawn was the time of day upon waking that the activities described by the source glyph were generally performed by bonobo-like tribes of early human beings. The day of Setsubun (see 節 for more details) formerly the dawning of the lunar new year (predating the solar calendar of January 1) encompasses an old, almost ignored tradition of eating an entire, uncut long roll of makizushi without speaking, and while most sources will no longer admit it, the analogy on this day in particular with「eating a long one quietly」(as fellating) is known among older folks in Japan, but not taught any longer to young children for reasons of a changing societal norm, and this tradition is fading as a consequence (no loss, though).
　People in a FEMALE ROLE performing fellatio with elements of「tonguing mouth array」recalling that in China female kin starting from the age of a very young child were often taught and trained, sold as sex slaves and prostitutes, in order to perform this very act for their master on command, and that therefore men were purchasing child slaves for just this purpose. Formerly elements of「person looking upward (short stature? or, due to kneeling?) and in some danger, perhaps of being squirted in the face」peering up beside「copulating, bent legs」with「fellating foreplay.」「In traditional Chinese medicine, there has never been a mental disease called pedophilia (or an equivalent term). …Children are usually described as natural sexual beings and erotic stimulation and sex-play are seen as beneficial to their healthy development.」
　　[　https://docx2.com/wp-content/uploads/Are-Any-of-the-Pharaphilias-in-DSM-Mental-Disorders_.pdf 2023-05-14　]　
　In Chinese meaning EXCELLENT, as in the most excellent position for a HUSBAND to have and as a broad, sweeping statement regarding a female's role, duties. Extended meanings of BRAGGART and LOQUACIOUS perhaps stem from the copious tonguing and mouth movements required while in such a position (the female role, not the man standing), but may also be derived from the HUSBAND later discussing the moment with his homies. TALKING TOO MUCH is exaggeratedly and graphically depicted in this scene since anything enunciated by the fellatrix would be talking too much for the client, other than uttering a sustained humming sound. ON THE VERGE, or ON THE EDGE is clearly related to the imminent danger of being struck in an open eye or the face and hair by an ejaculating burst, not unlike the first rays at the crack of DAWN. CLIENT OF A BROTHEL refers to an oft-requested form of service.
　Also meaning in Chinese,「egg」as a term of derision when combined with「turtle」to depict a child born of a married woman who has a different biological father than the wife's legal husband, a bastard from an adulterous whoring wife who enjoys 'sucking anyone' (some do, some do…) and a wimpy dad with a 'contracting turtle head and neck as his penis,' deriding all three persons as perhaps the worst possible insult in classical Chinese…and what does that have to do with「dawn」?

Modern definitions (that generally disregard history) …excluding politically incorrect concepts and other meanings deemed offensive today; may list only pigeonholed definitions, euphemisms, or meaningless mnemonics)
Chinese: dawn; morning; day-break; day
Japanese: husband
Unihan extended: dawn; morning; day
EDRDG: daybreak; dawn; morning