The most common and most likely answer to this crossword clue is the 2 letter word CH
I've seen this crossword clue in The Daily Telegraph
C
H
Buddy explains!

The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
Crossword Answer definitions
CH noun- A series of interconnected rings or links usually made of metal.
- A series of interconnected things.
- A series of stores or businesses with the same brand name.
- A number of atoms in a series, which combine to form a molecule.
- A series of interconnected links of known length, used as a measuring device.
- A long measuring tape.
- A unit of length equal to 22 yards. The length of a Gunter's surveying chain. The length of a cricket pitch. Equal to 20.12 metres, 4 rods, or 100 links.
- A totally ordered set, especially a totally ordered subset of a poset.
- A sequence of linked house purchases, each of which is dependent on the preceding and succeeding purchase (said to be "broken" if a buyer or seller pulls out).
- That which confines, fetters, or secures; a bond.
- (in the plural) Iron links bolted to the side of a vessel to bold the dead-eyes connected with the shrouds; also, the channels.
- The warp threads of a web.
- The physical confine of a river or slough, consisting of a bed and banks.
- The natural or man-made deeper course through a reef, bar, bay, or any shallow body of water.
- The navigable part of a river.
- A narrow body of water between two land masses.
- Something through which another thing passes; a means of conveying or transmitting.
- A gutter; a groove, as in a fluted column.
- A connection between initiating and terminating nodes of a circuit.
- The narrow conducting portion of a MOSFET transistor.
- (communication) The part that connects a data source to a data sink.
- (communication) A path for conveying electrical or electromagnetic signals, usually distinguished from other parallel paths.
- (communication) A single path provided by a transmission medium via physical separation, such as by multipair cable.
- (communication) A single path provided by a transmission medium via spectral or protocol separation, such as by frequency or time-division multiplexing.
- A specific radio frequency or band of frequencies, usually in conjunction with a predetermined letter, number, or codeword, and allocated by international agreement.
- A specific radio frequency or band of frequencies used for transmitting television.
- (storage) The portion of a storage medium, such as a track or a band, that is accessible to a given reading or writing station or head.
- (technic) The way in a turbine pump where the pressure is built up.
- A distribution channel
- A particular area for conversations on an IRC network, analogous to a chat room and often dedicated to a specific topic.
- An obsolete means of delivering up-to-date Internet content.
- A psychic or medium who temporarily takes on the personality of somebody else.
- The wale of a sailing ship which projects beyond the gunwale and to which the shrouds attach via the chains. One of the flat ledges of heavy plank bolted edgewise to the outside of a vessel, to increase the spread of the shrouds and carry them clear of the bulwarks.
- The speaker or writer, referred to as the grammatical subject, of a sentence.
- The speaker or writer, referred to as the grammatical object, of a sentence.