Contact has (or at least, use to have) at least 3 different meanings in the military flying world:
1. "Contact left 5 deg, 20 miles, 1000ft above" = I have traffic on radar (as stated).
2. "Contact Neatishead on TAD 123" = Call that GCI controller on (whatever UHF frequency Tactical Air Designator 123 decodes as). Although I thiink that was eventually changed from "contact" to "call".
3. "Contact, grid 123456" = there's a firefight at (wherever 123456 is).
And as for 'secure'..... "Secure the building" to a pongo means smash the door down, check the rooms are clear of hostiles. To a fishead it means lock the building up and b*gger off for the weekend. To the RAF it probably means make sure that we have the use of the building.
Ha! Now that made me laugh! Although for the RAF we viewed secure as leaving some rock ape in DPM with SLR/SA80 making it look occupied while we bogged off to the mess for a dining in/out....