Comment by claudius

    $ apropos space
    CORE (3perl)         - Namespace for Perl's core routines
    arpd (8)             - userspace arp daemon.
    CMSG_SPACE (3)       - access ancillary data
    CUDA_ERROR_INVALID_ADDRESS_SPACE (3) - (unknown subject)
    cudaErrorInvalidAddressSpace (3) - (unknown subject)
    df (1)               - report file system disk space usage