LATIN DICTIONARYLexicon Latīnum
verbirregular conjugation, suppletive, no passive, no supine stem except in the future active participle, no gerund

subsum

subsum (present infinitive subesse, perfect active subfuī, future active participle subfutūrus)
Classical[ˈsʊp.sũː]Ecclesiastical[ˈsub.sum]

Meaning

  1. intransitivesuppletiveto be under, among or behind
    Petimus eciam non haberi pro ingrato, quod premissa non prius fecimus vobis intimari; causa suffuit, quod hujusmodi tribulacio mercatoribus evenit ita repentino, quod vestri presenciam ad hoc non poterant habere commodose.We pray also that it will not be deemed ungrateful that the aforesent matters have not been intimated by us before; the underlying cause was (lit. the cause underlay) that a trouble of this kind went out so sudden to the merchants that they could not have your presence without inconvenience.1361 November 19, “Lübeck an Reval: theilt die Aug. 1 zu Greifswald von den Seestädten gefassten Beschlüsse mit”, in Hanserecesse, volumes I Die Recesse und andere Akten der Hansetage von 1256–1430, Leipzig: Duncker & Humblot, published 1870, page 193:
  2. intransitivesuppletiveto be at the bottom
  3. intransitivesuppletiveto be nearby

In the readers how our graded readers gloss it

Conjugation future irregular no supine

active indicative
formpresentimperfectfutureperfectpluperfectfut. perfect
1st sg.subsumsuberamsuberōsubfuīsubfueramsubfuerō
2nd sg.subessuberāssuberis
subere
subfuistīsubfuerāssubfueris
3rd sg.subestsuberatsuberitsubfuitsubfueratsubfuerit
1st pl.subsumussuberāmussuberimussubfuimussubfuerāmussubfuerimus
2nd pl.subestissuberātissuberitissubfuistissubfuerātissubfueritis
3rd pl.subsuntsuberantsuberuntsubfuērunt
subfuēre
subfuerantsubfuerint
active subjunctive
active subjunctive
formpresentimperfectperfectpluperfect
1st sg.subsim
subsiem, subfuam
subessem
subforem
subfuerimsubfuissem
2nd sg.subsīs
subsiēs, subfuās
subessēs
subforēs
subfuerīssubfuissēs
3rd sg.subsit
subsiet, subfuat
subesset
subforet
subfueritsubfuisset
1st pl.subsīmus
subsiēmus, subfuāmus
subessēmus
subforēmus
subfuerīmussubfuissēmus
2nd pl.subsītis
subsiētis, subfuātis
subessētis
subforētis
subfuerītissubfuissētis
3rd pl.subsint
subsient, subfuant
subessent
subforent
subfuerintsubfuissent
imperative
imperative
formactivepassive
pres. 2nd sg.subes—
pres. 2nd pl.subeste—
fut. 2nd sg.subestō—
fut. 3rd sg.subestō—
fut. 2nd pl.subestōte—
fut. 3rd pl.subsuntō—
infinitives & participles
infinitives & participles
formactivepassive
present infinitivesubesse—
perfect infinitivesubfuisse—
future infinitivesubfutūrum esse
subfore
—
future participlesubfutūrus—

Phrases from Meissner's Latin Phrase-Book

hiems subest
winter is at hand.

sub-sum, no
I. perf., esse, v. n., to be under, among, or behind; to be near, close, or at hand (class.): ubi non subest, quo praecipitet ac decidat, there is nothing underneath, Cic. Rep. 1, 45, 69; Lucr. 3, 873; cf. id. 4, 1082: si quid intra cutem subest ulceris, Planc. ap. Cic. Fam. 10, 18, 3: subucula subest tunicae, Hor. Ep. 1, 1, 96: nigra subest lingua palato, Verg. G. 3, 388: suberat Pan ilicis umbrae Tib. 2, 5, 27: cum sol Oceano subest, Hor. C. 4, 5, 40.—
B. To be near, to be at hand, of places and persons: mons suberat, Caes. B. G. 1, 25: montes, id. B. C. 1, 65: vallis, id. ib. 1, 79: planities, Liv. 27, 18: vicina taberna, Hor. Ep. 1, 14, 24: templa mari, Ov. M. 11, 359; cf.: regnum Ariobarzanis illi, Sall. Ep. Mithrid. ad Arsac. med.: me subesse propinquis locis, Planc. ap. Cic. Fam. 10, 21, 2.—
2. Transf., of time, to be near or at hand, to approach: nox jam suberat, was near, Caes. B. C. 3, 97; so, hiems, id. B. G. 3, 27: dies comitiorum, Cic. Mil. 16, 42.—
II. Trop., to be underneath, be at the bottom, be or exist under, lie concealed in: in quā (legatione) periculi suspitio non subesset, Cic. Phil. 9, 2, 4: in quā re nulla subesset suspitio, id. Rosc. Am. 10, 28; and simply suspitio, id. Quint. 21, 66: eadem causa subest, id. Off. 1, 12, 38: causa aliqua, id. Fin. 5, 10, 29; cf.: si his vitiis ratio non subesset, id. N. D. 3, 28, 71: ratio, Auct. Her. 1, 17, 27; Quint. 9, 3, 6: si negabimus temere famam Naxi solere, quin subsit aliquid, Auct. Her. 2, 8, 12: si ulla spes salutis nostrae subesset, Cic. Att. 3, 25: nam illi regi amabili, Cyro, subest ad inmutandi animi licentiam crudelissimus ille Phalaris, id. Rep. 1, 28, 44; Quint. 3, 5, 9: saepe solent auro multa subesse mala, are hid under, exist under, Tib. 1, 9, 18: subest silentio facinus, Curt. 6, 9, 11 et saep.— Poet.: notitiae suberit amica tuae, will be subject to your cognizance, Ov. A. A. 1, 398.

Origins

  1. Proto-Indo-European*upó
  2. Proto-Italic*supo
  3. Latinsubsum

Latin sub- Proto-Indo-European *h₁es- Proto-Indo-European *h₁ésti Proto-Indo-European *bʰuH- Proto-Indo-European *-t Proto-Indo-European *bʰúHt Proto-Italic *ezom~*som Archaic Latin 𐌄𐌔𐌏𐌌 (esom) Old Latin esum Latin sum Latin subsum From sub- + sum.

Quick answers

What does subsum mean in Latin?
subsum, a verb, means “to be under, among or behind; to be at the bottom; to be nearby”.
What are the principal parts of subsum?
subsum, subesse, subfuī, subfutūrus (irregular conjugation, suppletive, no passive, no supine stem except in the future active participle, no gerund).
How do you pronounce subsum?
In classical Latin, [ˈsʊp.sũː]; in ecclesiastical (church) Latin, [ˈsub.sum].
Where does subsum come from?
Proto-Indo-European *upó → Proto-Italic *supo → Latin subsum.