6. Loss of ............... contact may be the first indication of a plane's crash.
con·tact ( k¼n"t²kt") n. 1. a. A coming together or touching, as of objects or surfaces. b. The state or condition of touching or of immediate proximity: Litmus paper turns red on contact with an acid. 2. a. Connection or interaction; communication: in contact with the right people. b. Visual observation: The pilot made contact with the ship. c. Association; relationship: came into contact with new ideas at college. 3. A person who might be of use; a connection. 4. Electricity a. A connection between two conductors that permits a flow of current. b. A part or device that makes or breaks such a connection. 5. Medicine A person recently exposed to a contagious disease, usually through close association with an infected individual. 6. A contact lens. v. con·tact·ed con·tact·ing con·tacts ( k¼n"t²kt", k …n-t²kt") v. tr. 1. To bring or put in contact. 2. To get in touch with; communicate with: " This past January I was contacted by a lawyer who said he needed my help " Elizabeth Loftus v. intr. 1. To be in or come into contact. adj. 1. Of, sustaining, or making contact. 2. Caused or transmitted by touching: a contact skin rash. [Latin cont³ctus,from past participle of contingere to touch com- com- tangere to touch; See tag- in Indo-European Roots.] con·tac "tu·al ( k…n-t²k"ch›-…l) adj. con·tac "tu·al·ly adv.

Usage Note: In 1966 Wilson Follett wrote that " Persons old enough to have been repelled by the verb contact . . . may as well make up their minds that there is no way to arrest or reverse the tide of its popularity. " His prophecy is proving correct: In 1969 only 34 percent of the Usage Panel accepted the use of contact as a verb, but in our most recent survey 65 percent of the Panel accepted the sentence She immediately called an officer at the Naval Intelligence Service, who in turn contacted the FBI. See note at impact .

tag- . Important derivatives are: tact tangent tangible taste tax attain contact intact entire integer contaminate To touch, handle. I. 1. Nasalized form *ta-n-g- . TACT , TANGENT , TANGIBLE , TASTE , TAX ; ATTAIN , CONTACT , INTACT , TACTORECEPTOR , TANGORECEPTOR , from Latin tangere , to touch, with derivatives tax ³re, to touch, assess (possibly a frequentative of tangere , but probably influenced by Greek tassein , taxai , to arrange, assess), and t ³ctus, touch. 2. Compound form * ö-tag-ro-, " untouched, intact " ( * ö-, negative prefix; see ne ). ENTIRE , INTEGER , INTEGRATE , INTEGRITY , from Latin integer , intact, whole, complete, perfect, honest. 3. Suffixed form *tag-smen- . CONTAMINATE , from Latin cont ³min³re, to corrupt by mixing or contact ( < *con-t ³men-, " bringing into contact with "; con- , com- , with; see kom ). [ Pokorny tag- 1054. ]

ra·dar ( r³"där) n. 1. A method of detecting distant objects and determining their position, velocity, or other characteristics by analysis of very high frequency radio waves reflected from their surfaces. 2. The equipment used in such detection. n. attributive. 1. Often used to modify another noun: radar technology; a radar installation. [ ra(dio) d(etecting) a(nd) r(anging) ]

ra·di·o ( r³"d¶-½) n. pl. ra·di·os Abbr. rad. 1. The wireless transmission through space of electromagnetic waves in the approximate frequency range from 10 kilohertz to 300,000 megahertz. 2. Communication of audible signals encoded in electromagnetic waves. 3. Transmission of programs for the public by radio broadcast. 4. a. An apparatus used to transmit radio signals; a transmitter. b. An apparatus used to receive radio signals; a receiver. c. A complex of equipment capable of transmitting and receiving radio signals. 5. a. A station for radio transmitting. b. A radio broadcasting organization or network of affiliated organizations. c. The radio broadcasting industry. 6. A message sent by radio. n. attributive. 1. Often used to modify another noun: radio stations; radio programs. v. ra·di·oed ra·di·o·ing ra·di·os v. tr. 1. To transmit by radio: radio a message to headquarters. 2. To transmit a message to by radio: radioed the spacecraft. v. intr. 1. To transmit messages or a message by radio: a ship radioing for help. [Short for radiotelegraphy ]

ra·dix ( r³"d¹ks) n. pl. rad·i·ces ( r²d"¹-s¶z", r ³"d¹-) or ra·dix·es 1. Biology A root or point of origin. 2. Abbr. rad. Mathematics The base of a system of numbers, such as 2 in the binary system and 10 in the decimal system. [Latin r³dºx root; See wr ³d- in Indo-European Roots.]

wr ³d-. Important derivatives are: root 1 wort radical radish eradiate ramify licorice Branch, root. I. Basic form *wr ³d-. ROOT 1 ; RUTABAGA , from Old Norse r ½t, root, from Germanic *wr ½t-. II. Zero-grade form *w —…d-. 1. a. WORT 1 , from Old English wyrt , plant, herb; b. GEWüRZTRAMINER , from Old High German wurz , plant, root; c. MANGEL-WURZEL , from German Wurzel , root ( < *wurzwala , rootstock; *-wala , a roll, round stem; see wel- 2 ). a, b, and c all from Germanic *wurtiz . 2. Suffixed form *w —…d-y³-. WORT 2 , from Old English wyrt , brewer's wort, from Germanic *wurtj ½-. 3. RADICAL , RADICLE , RADISH , RADIX ; DERACINATE , ERADICATE , from Latin r ³dºx, root. 4. Suffixed form *wr …d-mo-. RAMOSE , RAMUS ; RAMIFY , from Latin r ³mus, branch. 5. Perhaps suffixed reduced form *w —(…)d-ya. RHIZO- , RHIZOME ; COLEORHIZA , LICORICE , MYCORRHIZA , from Greek rhiza , root. [ Pokorny ø (e)r³d- 1167. ]

ra·don ( r³"d¼n) n. Symbol Rn 1. A colorless, radioactive, inert gaseous element formed by the radioactive decay of radium. It is used as a radiation source in radiotherapy and to produce neutrons for research. Its most stable isotope is Rn 222 with a half-life of 3.82 days. Atomic number 86; melting point - 71°C; boiling point - 61.8°C; specific gravity (solid) 4. See note at element . [ rad(ium) -on 2 ]