Sure, building strong and defined abs requires a combination of targeted exercises and a well-rounded fitness routine that includes proper nutrition and overall body training. Here's a sample routine focusing on abs:

### Workout Structure:
**Frequency:** 2-3 times per week (Allow for rest days in between for muscle recovery)

**Exercises:** Choose a variety of exercises that target different areas of your abdominal muscles.

#### Sample Abs Workout Routine:

1. **Plank:**
- Hold for 30-60 seconds.
- Repeat for 3-4 sets.

2. **Crunches:**
- 15-20 reps per set.
- Aim for 3-4 sets.

3. **Leg Raises:**
- 10-15 reps per set.
- Perform 3-4 sets.

4. **Russian Twists:**
- 12-15 twists (each side) per set.
- Aim for 3-4 sets.

5. **Mountain Climbers:**
- 20-30 reps (each leg) per set.
- Repeat for 3-4 sets.

6. **Hanging Leg Raises:**
- 10-12 reps per set.
- Perform 3-4 sets.

### Tips for Effective Ab Training:

- **Proper Form:** Focus on executing each movement with proper form rather than quantity.

- **Progressive Overload:** Increase the difficulty or resistance gradually to keep challenging your muscles. This could involve adding weights, increasing reps, or trying advanced variations.

- **Consistency:** Consistency is key. Regularly train your abs and allow them time to recover.

- **Full-Body Training:** Compound movements like squats, deadlifts, and overhead presses engage the core significantly. Include these exercises in your routine for overall core strength.

### Nutrition for Abs Development:

Abs are also made in the kitchen! A balanced diet is crucial for revealing your abs:

- **Caloric Balance:** Maintain a slight caloric deficit if your goal is to reveal your abs by reducing body fat.

- **Protein Intake:** Adequate protein supports muscle recovery and growth.

- **Healthy Fats & Carbs:** Include healthy fats (avocado, nuts) and complex carbs (vegetables, whole grains) for energy and overall health.

Remember, visible abs also depend on your body fat percentage. Even with strong abs, they may not show if they're covered by a layer of fat. So, a combination of training, nutrition, and overall body fat reduction is key for well-defined abs.