You have encounter a software bug: CSCva24843
Below is a copy/paste from Cisco Bug Search:
ACI | Shorthand for "terminal length 0" does not work
User enters "term len 0" to disable paging in ACI but still has paging enabled when running a command with large output.
User does not spell out "terminal" completely.
User must spell out "terminal" completely (e.g. "terminal len 0").
Further Problem Description: None.
Cisco Application Policy Infrastructure Controller (APIC)
The command is exactly the same as all other Cisco equipment, this is copy/paste from the complete APIC-EM command line:
Description: Enable or disable pager for command output
Terminal length keyword
Terminal pager length (0=Disable pager). Number range from=0 to=511
Command Mode: exec : Exec Mode
# terminal length <NUMBER>
Cisco bug: https://bst.cloudapps.cisco.com/bugsearch/bug/CSCva24843/?rfs=iqvred
Complete APIC-EM command line: https://www.cisco.com/c/en/us/td/docs/switches/datacenter/aci/apic/sw/3-x/cli/nx/cr301/b_APIC_NXOS_CLI_Cmd_Reference_301/b_APIC_NXOS_CLI_Cmd_Reference_301_chapter_010100.html#wp2407208257