Clear explaination of how of arguments using multiple term names please

The Or module is an interesting option, but the post was to ask how to pass term names as opposed to id numbers to the view. Most of the uses I have at the moment, the arguments will be passed from Viewfield where the editors can add comma separated keywords for the view to display (the keywords in the above case correspond to taxonomy term names). In my case the operation is an AND, but I am unable to pass the names as arguments. There is no way the editors will be able to work out the Term Id numbers so I imagine the view has to convert the term name into a term id? I am missing how to do that. Thanks

Sorry about version number, no idea why it went to that - will take more care in future. Thanks for the explanation, which is something I had tried and have tried and tried again. And still not getting the results. The view return only the results for the first term in the argument.
My set up is: Argument: Taxonomy: Term ID. Action to take if argument is not present: Display all values. Validator: taxonomy term. Vocabularies: relevant checked. Argument type: Termname/synonym coverted to Term ID. Allow multiple terms per argument: checked. In the Live preview I separate the taxonomy terms (city names) with /. I am needing and testing this with Gmap views.

Query

SELECT node.nid AS nid,
node_revisions.title AS node_revisions_title,
node_revisions.nid AS node_revisions_nid,
node.type AS node_type,
node.vid AS node_vid,
node_data_field_summary.field_summary_value AS node_data_field_summary_field_summary_value,
node_data_field_summary.field_summary_format AS node_data_field_summary_field_summary_format,
location.longitude AS location_longitude,
location.latitude AS location_latitude,
location.latitude AS gmap_lat,
location.longitude AS gmap_lon,
node.type AS gmap_node_type
FROM node node
INNER JOIN term_node term_node_value_0 ON node.vid = term_node_value_0.vid AND term_node_value_0.tid = 133
LEFT JOIN node_revisions node_revisions ON node.vid = node_revisions.vid
LEFT JOIN content_field_summary node_data_field_summary ON node.vid = node_data_field_summary.vid
LEFT JOIN location_instance location_instance ON node.vid = location_instance.vid
LEFT JOIN location location ON location_instance.lid = location.lid
WHERE (node.type in ('accomm_list')) AND (term_node_value_0.tid = 133)

With argument as Node ID and basic validation with Allow multiple terms per argument checked, I can use multiple arguments using the term ID numbers and not putting a forward slash to separate the numbers (3 4 5 and not 3/4/5) unlike the Live Preview arguments box says to do: "Separate arguments with a / as though they were a URL path." However, when I change the settings for validator to be Term, with Argument type: Termname/synonym converted to Term ID, no query is run when I separate the arguments like cityx cityy with no slash. The only time a query is run is when there is a forward slash but takes first term only. I have now tried this on several different Drupal installs.