I'll take a shot a couple of these...
An op-amp is a "universal" low power amplifier chip. An ideal op-amp has infinite "open loop" gain and real op-amps have very high gain. That allows you to build amplifier where the gain is controlled by the ratio of two resistors. They can be used as a microphone preamp or to amplify other low-level signals.
They can also be used to make a high-pass or low-pass (or bandpass or band-reject) filter. Open loop (nearly infinite gain) they can be used as an analog comparator where the output is at the minimum voltage when the input is below the reference and "slammed" to the maximum output voltage when the input is above the reference. Here is a "famous" collection of op-amp circuits. (These are not complete schematics. Op-amps require power, and usually plus and minus power supplies with bypass capacitors on the power pins, etc.)
It simply means connected one-after-another. They are serially addressed and they have 8 outputs which can be connected to LEDs (etc.), If you daisy-chain 3 of them you can address/control 24 LEDs independently. You can daisy-chain an almost unlimited number of chips and individually control a huge number of LEDs with just a few Arduino output pins.
Analog-to-digital and digital-to-analog converter. An ADC has an analog input and a DAC has an analog output. The bits are binary (base-2) "digits".
The basic Arduino has a 10-bit ADC with a default 5V reference. With 5V on the ADC input you get the binary value of 1111111111 which is as high as you can count with 10 bits. We don't normally see the binary value and that converts to a decimal value of 1023. With 2.5V you get a decimal value of half the maximum (511 or 512).
The regular Arduino doesn't have a DAC (no true analog output). analogWrite() puts out PWM which can "simulate" analog to control the speed of a motor or change the apparent brightness of an LED, etc.
Real Time Clock = Time of day clock. An RTC module often also gives you the date. The Arduino only has a built-in clock that gives you the number of milliseconds since the Arduino was booted (IIRC it "rolls over" after about 45 days) but it doesn't know the time-of-day.