The true ancient meaning of Aleph/Tav comes from Aleph being God, strength,leader, Tav, being sign/covenant, mark, etc.
So it's ancient definition is 'strength of covenant" as well as first and last, beginning and end. In the modern translation (poorly they are) it is used incorrectly as you put it above. Hope this helps.
Baruchim
I think the word Truth would apply. Aleph Mem Tav is strong water mark if you define the letters. Sin is chet, or missing the mark. Originally, the Tav was the plowman's mark. The Ox (Aleph) followed the stringline to the mark. The furrow was straight and could receive seed.
Compared to this, the Ruach hovering over the waters was feminine. Aleph Mem is the Hebrew word Mother. Aleph Bet is Father (Letters). And the Son is Bet Nun, or House of Seed (loaf of bread).
The cup is the mother, receiving the Aleph Bet (letters), baking in an oven. Bread is the House of Seed, or Son (Ben).
If you then go back to the Word Truth (Strong Water Mark), you get all three members. Father (Aleph ), Mother (Mem) and Son (Tav), or mark to hit. Sin is missing the mark.
As Jesus stated, coming to the Father (letters) is only achieved by coming through the Word (Son). No one comes to the Father except through the word. Ox pulling the beasts through the water to the Tav. A-Z so to speak. Beginning and End.
In 1 Peter 3, we have the symbolism of the Ark saving the 8. The water saves us now (baptism). In other words, the Ark saved Noah. The water saves the beasts that failed to enter the Ark. God went after them too.
19 After being made alive, he went and made proclamation to the imprisoned spirits— 20 to those who were disobedient long ago when God waited patiently in the days of Noah while the ark was being built. In it only a few people, eight in all, were saved through water, 21 and this water symbolizes baptism that now saves you also—not the removal of dirt from the body but the pledge of a clear conscience toward God.
Of course, the conscience is the silencing of Satan (accuser) we read in Zechariah 3 and in the desert temptation of Christ. In both cases, Yahweh and the Branch he sent silenced Satan. How? Baptism. Christ made peace with the Father and Mother (Ruach / Dove) symbolically. In the Desert, he did it without water and food. Yahweh prepared the foundation (Joshua / High Priest / Yeshua) and Jesus was the temple built above ground. Water is the process of rebirth (transmigration) mentioned in Hebrews 11. Women received back their dead to live again. Some refused, desiring a better resurrection. Isaiah 26 then outlines this yet again with the dew and rail symbolism from 1 Kings 17, where Elijah (John the Baptist) raises the Son to life in resurrection. The mother (mem) received the dew and rain again. Understanding baptism as transmigration then solves the scattering of Israel with their Rock (1 Corinthians 10). They were in the wilderness from baptism, as it says. We have all been here for a long time.
I see this from the letters.
Of course, taking the Aleph from Emet makes Met (Death). The Father must be the strength of the House. The strength comes from his will to give and receive only. The thieves take. This is the nature of Sin on the Nun. The thorn of crowns was on the head (authority). As the Christmas song says, Sister Susie (Nun) sits on a thistle (Sin). All he wants for Christmas are his two front teeth (Shin). The flame that does not consume the coal (Carbon has 6 protons, 6 neutrons and 6 electrons). The mark of the beast is sin. The mark of God is the Strong Water Mark.
Letters show the Word. The Aleph Tav is the Strong Mark of Father and Son. The water is the Ruach.
If he has his two front teeth, he can whistle again.
Isaiah 5:26
He lifts up a banner for the distant nations, he whistles for those at the ends of the earth. Here they come, swiftly and speedily!
If Israel knew this, they would know Christ from a simple Christmas Song. It's not secular at all. The song writer never knew what he was inspired to write. The Son did. Inspiration comes from words. Once you know the Word, you can know the Aleph Bet.