The Collaborative International Dictionary of English v.0.48:

Safe \Safe\, n.
   A place for keeping things in safety. Specifically:
   (a) A strong and fireproof receptacle (as a movable chest of
       steel, etc., or a closet or vault of brickwork) for
       containing money, valuable papers, or the like.
   (b) A ventilated or refrigerated chest or closet for securing
       provisions from noxious animals or insects.
       [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Safe \Safe\, a. [Compar. Safer; superl. Safest.] [OE. sauf,
   F. sauf, fr. L. salvus, akin to salus health, welfare,
   safety. Cf. Salute, Salvation, Sage a plant, Save,
   Salvo an exception.]
   1. Free from harm, injury, or risk; untouched or unthreatened
      by danger or injury; unharmed; unhurt; secure; whole; as,
      safe from disease; safe from storms; safe from foes. "And
      ye dwelled safe." --1 Sam. xii. 11.
      [1913 Webster]

            They escaped all safe to land.        --Acts xxvii.
                                                  44.
      [1913 Webster]

            Established in a safe, unenvied throne. --Milton.
      [1913 Webster]

   2. Conferring safety; securing from harm; not exposing to
      danger; confining securely; to be relied upon; not
      dangerous; as, a safe harbor; a safe bridge, etc. "The man
      of safe discretion." --Shak.
      [1913 Webster]

            The King of heaven hath doomed
            This place our dungeon, not our safe retreat.
                                                  --Milton.
      [1913 Webster]

   3. Incapable of doing harm; no longer dangerous; in secure
      care or custody; as, the prisoner is safe.
      [1913 Webster]

            But Banquo's safe?
            Ay, my good lord, safe in a ditch he bides. --Shak.
      [1913 Webster]

   Safe hit (Baseball), a hit which enables the batter to get
      to first base even if no error is made by the other side.
      [1913 Webster]

   Syn: Secure; unendangered; sure.
        [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Safe \Safe\, v. t.
   To render safe; to make right. [Obs.] --Shak.
   [1913 Webster]

WordNet (r) 3.0 (2006):

safe
    adj 1: free from danger or the risk of harm; "a safe trip"; "you
           will be safe here"; "a safe place"; "a safe bet" [ant:
           dangerous, unsafe]
    2: (of an undertaking) secure from risk
    3: having reached a base without being put out; "the runner was
       called safe when the baseman dropped the ball" [ant:
       out(p)]
    4: financially sound; "a good investment"; "a secure investment"
       [syn: dependable, good, safe, secure]
    n 1: strongbox where valuables can be safely kept
    2: a ventilated or refrigerated cupboard for securing provisions
       from pests
    3: contraceptive device consisting of a sheath of thin rubber or
       latex that is worn over the penis during intercourse [syn:
       condom, rubber, safety, safe, prophylactic]

Moby Thesaurus II by Grady Ward, 1.0:

135 Moby Thesaurus words for "safe":
   Fort Knox, OK, acceptable, all right, allowable, appropriate,
   armed, bank, bona fide, bursary, calculating, canny, careful,
   cash register, cashbox, cautious, chary, chest, circumspect,
   cloaked, coffer, coin box, conservative, considerate, copyrighted,
   correct, covered, crypt, defended, deliberate, dependable,
   depository, discreet, exchequer, fisc, gingerly, gold depository,
   guarded, guarding, harmless, healthy, heedful, hesitant, immune,
   immunized, impregnable, innocent, innocuous, inoffensive, insured,
   intact, inviolable, invulnerable, judicious, justifiable,
   justified, leaving out nothing, locker, mindful, money chest,
   noncommittal, okay, on guard, overlooking no possibility, patented,
   pawky, penny bank, permissible, piggy bank, policed, politic,
   pork barrel, proper, protected, protecting, prudent, public crib,
   public till, public treasury, public trough, regardful, reliable,
   repository, right, riskless, safe and sound, safe-deposit box,
   safeguarded, safeguarding, safely, satisfactory, scatheless,
   screened, secure, secured, securely, sheltered, sheltering,
   shielded, shielding, slow to act, solid, sound, storehouse,
   strong room, strongbox, subtreasury, suitable, sure, tentative,
   thorough, till, timely, treasure-house, treasury, tried and true,
   unadventurous, unassailable, uncommunicative, undamaged, undaring,
   unenterprising, unharmed, unhurt, uninjured, uninjurious,
   unpolluted, unprecipitate, unscathed, unthreatened, untouched,
   vault, wary, whole, wholesome



V.E.R.A. -- Virtual Entity of Relevant Acronyms (February 2016):

SAFE
       Security And Freedom through Encryption [law] (USA, cryptography)


The Free On-line Dictionary of Computing (30 December 2018):

safe

   A safe program analysis is one which will not reach invalid
   conclusions about the behaviour of the program.  This may
   involve making safe approximations to properties of parts of
   the program.  A safe approximation is one which gives less
   information.

   For example, strictness analysis aims to answer the question
   "will this function evaluate its argument"?.  The two possible
   results are "definitely" and "don't know".  A safe
   approximation for "definitely" is "don't know".  The two
   possible results correspond to the two sets: "the set of all
   functions which evaluate their argument" and "all functions".
   A set can be safely approximated by another which contains it.