Alif Lam Mim means nothing. Knowledge of these words are with Allah alone
Arabic and hebrew have root words. eg:
Ḥaa-Raa-Meem or H -R -M
Mahram — "forbidden" — "not need to
Ihram — Hajj cloth, and the state of ritual consecration
Harem — "forbidden place" — woman part of house, forbidden for non-Mahram men
Halal and Haraam foods
Ḥarām — ritually impure
Ḥaram — sanctuary
Herem (Hebrew) — - Excommunication,
Hahrama (Hebrew) — - Confiscation (civil law)
Similarly this could be a root word for something more.
This is What Rashad Khalifah says.
*[2:1and 3:1] These initials remained a divinely guarded secret for 1400 years. Now we recognize them as a major component of the Quran's mathematical miracle (see Appendices 1, 2, 24, and 26). The meaning of A.L.M. is pointed out in Verse 2: "This scripture is infallible." This is incontrovertibly proven by the fact that the frequencies of
occurrence of these three initials in this sura are 4502, 3202, and 2195, respectively. The sum of these numbers is 9899, or 19x521. Thus, these most frequent letters of the Arabic language are mathematically placed according to a superhuman pattern. These same initials also prefix Suras 3, 29, 30, 31, and 32, and their frequencies of occurrence add up to multiples of 19 in each one of these suras.