| Jack Palance | Jack Palance |
| Jack Ruby | Jack Ruby |
| Jack Russell | John Russell |
| Jack Russell Terrier | Jack Russell Terrier |
| Jack Shephard | Jack Shephard |
| Jack Skellington | Jack Skeletron |
| Jack Sparrow | Jack Sparrow |
| Jack Steinberger | Jack Steinberger |
| Jack Straw | Jack Straw |
| Jack Swigert | Jack Swigert |
| Jack the Ripper | Jack lo squartatore |
| jack up | sollevare con il cric |
| Jack Vance | Jack Vance |
| Jack Williamson | Jack Williamson |
| Jack-Jack Attack | Jack-Jack Attack |
| jack-plane | sbozzino |
| jackal | sciacallo |
| Jackalope | Jackalope |
| jackass | sciocco |
| jackass hare | lepre nordamericana |
| jackboots | stivali con ginocchiera |
| jackdaw | taccola |
| jacket | giacca |
| Jacketa | Jacketa |
| Jackie Brown | Jackie Brown |
| Jackie Chan | Jackie Chan |
| Jackie Coogan | Jackie Coogan |
| Jackie Stewart | Jackie Stewart |
| jackknife | coltello a serramanico |
| jackpot | posta |
| jackrabbit | lepre nordamericana |
| Jackson | Jackson |
| Jackson County | Contea di Jackson |
| Jackson Guitars | Jackson |
| Jackson Pollock | Jackson Pollock |
| Jackson Showalter | Jackson Showalter |
| Jacksonville | Jacksonville |
| Jacksonville Jaguars | Jacksonville Jaguars |
| Jacky Ickx | Jacky Ickx |
| Jaco Pastorius | Jaco Pastorius |
| Jacob | Giacomo |
| Jacob Abbott | Jacob Abbott |
| Jacob Acontius | Jacopo Aconcio |
| Jacob Bekenstein | Jacob Bekenstein |
| Jacob Bernoulli | Jakob Bernoulli |
| Jacob Burckhardt | Jacob Burckhardt |
| Jacob Clemens non Papa | Jacob Clemens non Papa |
| Jacob Friedrich von Abel | Jakob Friedrich von Abel |
| Jacob Fugger | Jacob Fugger |
| Jacob Hutter | Jakob Hutter |
| Jacob Hübner | Jacob Hübner |
| Jacob Isaakszoon van Ruysdael | Jacob van Ruisdael |
| Jacob Johan Anckarström | Jacob Johan Anckarström |
| Jacob Jordaens | Jacob Jordaens |
| Jacob Kettler | Jacob Kettler |
| Jacob Philipp Hackert | Jakob Philipp Hackert |
| Jacob Senleches | Jacob Senleches |
| Jacob the Liar | Jakob il bugiardo |
| Jacob Veldhuyzen van Zanten | Jacob Louis Veldhuyzen van Zanten |
| Jacobean | giacobino |
| Jacobi identity | Identità di Jacobi |
| Jacobi method | Metodo di Jacobi |
| Jacobi polynomials | Polinomi di Jacobi |
| Jacobi symbol | Simbolo di Jacobi |
| Jacobian | Matrice jacobiana |
| Jacobian matrix | Matrice jacobiana |
| Jacobin | giacobino |
| Jacobin Club | Giacobinismo |
| Jacobinism | Giacobinismo |
| Jacobite | Giacobitismo |
| Jacobite rising | Ascesa giacobita |
| Jacobitism | Giacobitismo |
| Jacobo Arbenz Guzmán | Jacobo Arbenz Guzmán |
| Jacobsen syndrome | Sindrome di Jacobsen |
| Jacobsite | Jacobsite |
| Jacobus de Voragine | Jacopo da Varazze |
| Jacobus Houbraken | Jacobus Houbraken |
| Jacobus Johannes Fouché | Jacobus Johannes Fouché |
| Jacobus Oud | Jacobus Johannes Pieter Oud |
| Jacoby Shaddix | Jacoby Shaddix |
| Jacoby transfer | Texas |
