These are the same as highlights but darker, rather than lighter than your own hair, produced using tints/permanent colour rather than bleach. Again there are lots of variations on the terminology so just check your hairdresser's definition when you chat about this type of colouring. Colours range from reds to coppers to aubergines and toffees the range is limitless, you can even get adventurous and try several different colours together.
Low lights are also an option if you want to disguise grey hair but not loose it all together. You can choose a colour that is the same as your natural colour and blend out some of your greys as low-lights will cover about 30 to 50% of your hair. As not all of the hair is coloured the re-growth will not be as strong and so only require touch-ups every 8 weeks plus. Remember the more contrasting the colour you chose to your grey hairs the more often it will need to be done.
The rest of the details regarding low-lights are exactly the same as for highlights.
Splices, slices, chunks or pieces
All of these terms are used to describe pieces of colour that are made using foil in the same way as high or low lights but are large sections of colour rather than strands. This type of colouring is as strong or as soft as the contrast of the chosen colour to the rest of your hair colour. Hairdressers often use this type of colouring to show off certain sections of your haircut or to add interest. It works especially well for those of you with curly hair as smaller strands of colour tend to get lost and you end up wondering what you have paid for! It's a good idea to find a picture of the type of texture you want from this type of colouring and to show the hairdresser because everyone's idea of the size of these pieces is different. Remember you don't have to find the exact colour in the picture, as it's the texture that's important.
Note: There is a variation on using foil to separate the hair for high or low-lighting and splices etc. using a type of plastic packet or glad wrap, that either sticks or clips to the hair. In competent hands these do work well, although the foil method when used by an expert can produce a more personalized look for you.
For more useful information on this topic also see choosing highlights.